ORGANIZING COMMITTEE - nap.sumdu.edu.ua

Ministry of Education & Science of Ukraine

Sumy State University

IEEE Nanotechnology Council

IEEE Magnetics Society

of the 2020 IEEE 10th

International Conference on

“Nanomaterials: Applications & Properties”

(NAP-2020)

ABSTRACTS

A Virtual Conference

November 09–13, 2020

Founded in 2011

Sumy


2020

2020 IEEE 10th International Conference on “Nanomaterials: Applications &

Properties” (NAP-2020)

COMMITTEES

ORGANIZING COMMITTEE

Alexander Pogrebnjak Sumy State University (Ukraine), General Chair

Valentyn Novosad IEEE Nanotechnology Council (USA), General Co-Chair

Goran Karapetrov Drexel University (USA), Technical Program Chair

Oleksandr Prokopenko Taras Shevchenko National University of Kyiv

(Ukraine), Technical Program Co-Chair

Maksym Pogorelov Sumy State University (Ukraine), Technical Program Co-Chair

Katerina Medjanik Johannes Gutenberg University of Mainz (Germany), Publication Chair

Yurii Shabelnyk Sumy State University (Ukraine), Secretary

Oleksii Drozdenko Sumy State University (Ukraine), Treasurer

Olena Tkach Sumy State University (Ukraine), WIE/WIS Chair

Anna Marchenko Sumy State University (Ukraine), Awards Chair

INTERNATIONAL SCIENTIFIC COMMITTEE

Valentyn Novosad IEEE Nanotechnology Council (USA), Chair

James E. Morris Portland State University (USA), Co-Chair

Alexander Pogrebnjak Sumy State University (Ukraine)

Andrii Chumak University of Vienna (Austria)

Bethanie Stadler University of Minnesota (USA)

Denise Erb Institute of Ion Beam Physics and Materials Research, HZDR (Germany)

Dmytro Nykypanchuk Brookhaven National Laboratory, Center for Functional Nanomaterials

(USA)

Fedir Sizov V.E. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine

(Ukraine)

Geraldine Dantelle Institut NEEL (France)

Haifeng Ding Nanjing University (China)

Jindrich Musil University of West Bohemia in Pilsen (Czech Republic)

Leonid Sukhodub Sumy State University (Ukraine)

Montserrat Rivas University of Oviedo (Spain)

Nicoletta Ditaranto University of Bari Aldo Moro (Italy)

Oksana Chubykalo-

Fesenko

CSIC - Instituto de Ciencia de Materiales de Madrid (Spain)

Oleg Lupan Technical University of Moldova (Moldova)

Oleksandr Tovstolytkin Institute of Magnetism NAS of Ukraine (Ukraine)

Pawel Zukowski Lublin University of Technology (Poland)

Tetsuya Nakamura Tohoku University (Japan)

Vladimir Cambel Institute of Electrical Engineering, SAS (Slovakia)

Vladimir Komanicky Pavol Jozef Safarik University (Slovakia)

Vojislav Mitic University of Nis (Serbia)

Volodymyr Ivashchenko Institute for Problems of Materials Science NAS of Ukraine (Ukraine)

Yonhua Tzeng National Cheng Kung University (Taiwan)

Yuko Ichiyanagi Yokohama National University (Japan)

Yury Gogotsi Drexel University (USA)

ORGANIZERS

MINISTRY OF EDUCATION AND

SCIENCE OF UKRAINE The Ministry of Education and Science implements Ukrainian

government policies in education and science. It also supports

and oversees a variety of fundamental research programs

performed in state-accredited universities.

SUMY STATE UNIVERSITY Sumy State University is one of top leading universities in

Ukraine of a classical type with the III-IV accreditation level in

the region. The University currently serves 14,000+ students

who are pursuing pre-bachelor, bachelor, specialist and master

degrees in 55 majors and 23 fields of knowledge. About 1800

foreign students represent almost 50 countries worldwide.

Broaden your international experience and study in Sumy State!

IEEE NANOTECHNOLOGY COUNCIL The IEEE Nanotechnology Council is a multi-disciplinary

group whose purpose is to advance and coordinate work in the

field of Nanotechnology carried out throughout the IEEE in

scientific, literary and educational areas. The Council supports

the theory, design, and development of nanotechnology and its

scientific, engineering, and industrial applications.

SPONSORS

ANGSTROM ENGINEERING, INC. Angstrom Engineering, Inc., founded in 1992, is a thriving

international company with an established reputation for

providing high-quality PVD (Physical Vapor Deposition) and

CVD (Chemical Vapor Deposition) tools and unparalleled

customer service. We are proud to manufacture the systems that

allow a wide variety of researchers and development teams in

world-class labs across the globe to innovate new technologies.

Reach to us today for all your thin film deposition tools!

IEEE MAGNETIC SOCIETY The IEEE Magnetics Society promotes the advancement of

science, technology, applications and training in magnetics-

related fields. It fosters presentation and exchange of

information among its members and within the global technical

community, including education and training of young

engineers and scientists. We seek to nurture positive

interactions between all national and regional societies acting in

the field of magnetism!

US-UKRAINE FOUNDATION

BIOTECHNOLOGY INITIATIVE

The US-Ukraine Foundation Biotechnology Initiative aims to

advance the state of biotech in Ukraine by fostering

educational, research and business development and raising

international awareness. The Foundation provides support to

Ukrainian students, researchers and entrepreneurs who wish to

engage with the international biotech community through

educational exchanges, and participation in trade shows and

conferences.

https://mon.gov.ua/eng

https://www.sumdu.edu.ua/int/en

https://ieeenano.org/

https://angstromengineering.com/

https://ieeemagnetics.org/

https://bioukraine.org/

ZEISS CONNECTING SOLUTIONS,

LCC Carl Zeiss develops and distributes technological solutions

to science, education, innovation industry, manufacturing, and

health service since 1846! ZEISS is active in four business

segments,- Industrial Quality and Research, Medical

Technology, Consumer Markets and Semiconductor

Manufacturing Technology, in almost 50 countries, has 30

production sites and around 25 development sites worldwide.

THATEC INNOVATION, GMBH THATec Innovation is a company founded by scientists for

scientists. Our motivation is to help you to stay focused on the

essential: your scientific work. The idea behind THATec

Innovation was born in the lab with the major goal to develop

hardware and software solutions to let you profit from our

experience in the areas of our expertise: the automation of

laboratory devices, optical scanning microscopy, and Brillouin

light scattering.

MEDIA PARTNERS

IEEE XPLORE DIGITAL LIBRARY IEEE Xplore is a scholarly research database that indexes,

abstracts, and provides full-text for articles and papers on

computer science, electrical engineering and electronics.

JOURNAL OF NANO- AND

ELECTRONIC PHYSICS Journal of Nano- and Electronic Physics (ISSN 2077-6772) is

peer-reviewed journal indexed by Scopus. Choose us to publish

your cutting-edge experimental and theoretical works in the

fields of condensed matter physics, nanoelectronics, and

materials science.

NANOMATERIALS Nanomaterials (ISSN 2079-4991; CODEN: NANOKO) is an

international and interdisciplinary scholarly open access

journal. We publish reviews, regular research papers,

communications, and short notes that are relevant to any field

of study that involves nanomaterials, and with respect to their

science and application.

https://www.zeiss.com/

https://thatec-innovation.com/

https://ieeexplore.ieee.org/

https://jnep.sumdu.edu.ua/en/

https://www.mdpi.com/journal/nanomaterials

С-1

Table of Contents

Microstructure and Tribomechanical Properties of WN-based Binary Multilayer Protective Coatings

K. Smyrnova, M. Sahul, A. Pogrebnjak, V. Beresnev, V. Stolbovoy, L. Čaplovič, M. Kusý,

M. Haršáni ............................................................................................................................................ 03TFC01

Design of LPE Growth n+–i–n

+ GaAs Structures with Submicron Layers for Gunn Diodes

S.I. Krukovskyi, I. Izhnin, B. Prytulyak ................................................................................................. 03TFC02

Tailoring Magnetic Anisotropies in Thin Film Structures Based on NixFe100-x Alloys

Ch. Gritsenko, V. Rodionova ................................................................................................................ 03TFC03

A New Combined Sputtering System for Complex Nanostructured Coatings Synthesis

S. Yakovin, A. Zykov, S. Dudin, N. Yefimenko....................................................................................... 03TFC04

New Type of Superhard Nanocomposite Coatings on the Basis Nanostructured AlTiN and Diamond-

Like Coatings - Orientant

L. Changhong, P. Ying, M. Huang, J. Wu, Zh. Ping, Y. Tao, V. Levchenko ......................................... 03TFC05

Surface Modifications of Detonation Nanodiamonds

J.C. Arnault ........................................................................................................................................... 03TFC06

Multilayer and High-Entropy Alloy-Based Coatings for Solving the Critical Raw Materials Problem

B. Postolnyi, V. Buranich, K. Smyrnova, J.P. Araújo, A. Pogrebnjak, V. Rogoz .................................. 03TFC07

Integration of Plasmonic and Si Nanophotonics Devices

V. Zayets ................................................................................................................................................. 03NP01

Luminescence Properties of Magnesium Aluminum Spinel in Nanocrystalline and Single-crystal

States with Cr-impurities

K.V. Lamonova, I. Danilenko, Yu. Kazarinov, S.M. Orel, Yu.G. Pashkevich ......................................... 03NP02

Thermally-induced Structural Phase Transitions in Pt/Fe Layered Stacks with Additional Layers of

Alloying Elements

I. Kruhlov, O. Shamis, N. Schmidt, G. Katona, M. Albrecht, I. Vladymyrskyi ................................... 03NMM01

Theory of Three-magnon Scattering in Vortex-state Magnetic Nanodisks

R. Verba, V. Tyberkevych, A. Slavin .................................................................................................. 03NMM02

Spintronic Devices for Efficient Computing

A. Hirohata, K. Elphick, W. Frost, E. Jackson, M. Samiepour, T. Seki, T. Kubota,

D. Takano, R. Ramos, E. Saitoh, K. Takanashi, T. Tsuchiya, T. Ichinose, S. Mizukami .................... 03NMM03

Magnetic Properties of Heavily Cr+-Implanted CdTe Single Crystals with Dopant-related

Nanoclusters

V. Popovych, S. Zhou, A. Żywczak, B. Cieniek, I. Stefaniuk, R. Böttger, M. Kuzma .......................... 03NMM04

Handling of Magnetic Properties of Ferromagnetic Micro Scale Materials with Curvy Geometry

V. Kolesnikova, N. Andreev, A. Bzlov, M. Rivas, V. Rodionova ........................................................ 03NMM05

A Cluster-glass Behavior of Co2+

-Containing Layered Double Hydroxide Intercalated with Nitrate

A. Fedorchenko, E. Fertman, V.V. Rubanik Jr, V.V. Rubanik, D.E.L. Vieira, A.N. Salak,

Yu. Pashkevich, R. Babkin ................................................................................................................. 03NMM06

С-2

The Internal Stresses Influence on the Magnetostatic, Magnetostrictive and Dynamic Properties of Fe-

based Amorphous Microwires

A.I. Litvinova, V.V. Rodionova .......................................................................................................... 03NMM07

Exchange Inertia Effects in Artificial Neural Networks Using Antiferromagnetic Oscillators

H. Bradle, V. Tyburkevych ................................................................................................................. 03NMM08

Unitary Magnon-mediated Quantum Computing Operations

C.A. Trevillian, V. Tyberkevych ......................................................................................................... 03NMM09

Thermal Noise Effects on Sweep-tuned Spectrum Analyzer Accuracy

P. Elphick, S. Louis, P. Artemchuk, V. Tyberkevych, A. Slavin ......................................................... 03NMM10

Longitudinal Relaxation of Domain Walls in Ultrathin Ferromagnets

I.A. Yastremsky, J. Fassbender, D. Makarov, N.E. Kulagin, B.A. Ivanov ......................................... 03NMM11

Circular Stripe Domains Imprinted into the Out-of-Plane Magnetised Material

O. Zaiets, D. Sheka, V. Kravchuk, D. Makarov ................................................................................. 03NMM12

Surface Magnon-Plasmon-Polariton Resonance in a Shielded Ferromagnetic Film

O.V. Malyshev, V. Malyshev, O. Prokopenko .................................................................................... 03NMM13

Magnonic Crystal Based on YIG/Hexaferite Films

V. Kariachka, V. Malyshev, O. Prokopenko, V. Romaniuk, V. Kostenko, D. Bozhko ........................ 03NMM14

Photovoltaic, Photocatalytic and Microfluidic Energy Harvesters for Autonomous Sensor Systems

I. Turkevych ............................................................................................................................................ 03NS01

Zinc Oxide Doped Tungsten Trioxide Nanostructure for Ethanol Gas Sensor Applications

G. Adilakshmi, A.S. Reddy, P.S. Reddy ................................................................................................... 03NS02

1D Nanostructure Materials for the Energy Conversion

Yu. Pihosh, V. Nandal, K. Seki, K. Domen............................................................................................ 03NEE01

Calcium Copper Titanate Based Nanocomposites for the Photoelectrocatalytic Wastewater Treatment

F. Tanos, A. Razzouk, M. Crettin, G. Lesage, M. Bechelany ................................................................ 03NEE02

Magnetic Field Assisted-Nanocatalysis for Industrial Wastewater Treatment

A. Gallo-Cordova, J.J. Castro, E.L. Winkler, E. Lima Jr., R.D. Zysler, M. del Puerto

Morales, J.G. Ovejero, D.A. Streitwieser ............................................................................................. 03NEE03

Evolution of Multicomponent Structures of Biopolymer Composites Under the Action of Severe

Plastic Deformation

A. Voznyak, G. Ivanova, I. Dovgoruk.................................................................................................... 03NEE04

The Electrophysical and Morphological Properties of Hydrothermal Synthesized CuFe2O4 and

CuFe2O4 / Reduced Graphene Oxide Composite

V.O. Kotsyubynsky, V.M. Boichuk, R.I. Zapukhlyak, M.A. Hodlevska, M.A. Hodlevskyi, A.I.

Kachmar ............................................................................................................................................... 03NEE05

Application of Nano Materials for the Treatment of Produced Water

K.T. Amakiri, A. Angelis-Dimakis, M. Molinari ................................................................................... 03NEE06

The Behaviors of Non-persistent Plasmonic Nano-architectures

С-3

V. Voliani ................................................................................................................................................ 03BA01

Composite on the Base of Natural Silicates (Zeolite, Kaolinite, Montmorillonite) and Plant Raw

Material for Food and Cosmetics Purposes: Nanocomposites and Nanohybrids

V.V. Paientko, A. Matkovsky, L. Babenko, N. Liedienov, A. Pashchenko, O. Yesypchuk,

V. Kostur, V. Zadorozniy ........................................................................................................................ 03BA02

Rescuing Neuroblastoma Cells from Oxidative Stress using Naturally-derived Graphene Quantum

Dots

J. Ahlawat, M. Narayan .......................................................................................................................... 03BA03

Composite of Cobalt Ferrite Nanoparticles Substituted with Zinc as Promicing Tool for Leukemia

Treatment

A. Motorzhina, S. Pshenichnikov, M. Vukomanovic, S. Jovanovic, K. Levada, V. Rodionova ............... 03BA04

Effect of Piezoelectric Composites on the Adhesion and Migration of Neuronal Stem Cells

V. Antipova, A. Amirov, K. Levada, Y. Han, E.N. Kozlova, V. Rodionova ............................................. 03BA05

Vortex States in Core-shell Ferroelectric Nanoparticles for Multi-bit Memory

A.N. Morozovska, E.A. Eliseev, R. Hertel, V.V. Tulaidan, V.Yu. Reshetnyak, D.R. Evans .................... 03TM01

Electronic and Optical Properties of 1T’-ReS2 Graphene van der Waals Heterostuctures

A. Sengupta ............................................................................................................................................ 03TM02

4D Printing using Anisotropy of Extrusion Type Additive Manufacturing

K. Park, B. Goo, Ch.-H. Hong .......................................................................................................... 03SAMA01

Extending the Use of Lignocellulosic Biomass in Additive Manufacturing Technology

M.Sh. Sajab, D. Mohan ..................................................................................................................... 03SAMA02

Additive Manufacturing of Brass Alloys

V.V. Popov, A. Fleisher, E. Strokin, A. Kovalevsky .......................................................................... 03SAMA03

Evaluation of 3D Printed Scaffolds for Tissue Engineering

A. Palojarvi, T. Nguyen, M. Kihlstrom, P. Singh .............................................................................. 03SAMA04

Numerical Simulation of Additive Manufacturing Process of Large Parts with Polyurethane Foams

E. Paquet, B. Furet, S. Garnier, S. Le Loch, A. Bernard .................................................................. 03SAMA05

Additive Manufacturing of Heavy Rare Earth Free High-coercivity Permanent Magnets

A. Volegov, S. Andreev, N. Selezneva, N. Kudrevatykh, I. Ryzhikhin, L. Mädler, I. Okulov ............. 03SAMA06

Electrically Conductive Adhesives as the New Materials for Fused Filament Fabrication 3D Printing

Process

P. Latko-Durałek, A.D. Lewis, D. Therriault .................................................................................... 03SAMA07

4D Printing: Functional and Microstructure Engineering in Powder Bed Additive Manufacturing

A. Koptyug, C. Botero, W. Sjöström, L.-E. Rännar, S. Roos, M. Bäckström..................................... 03SAMA08

IEEE International Conference on

“Nanomaterials: Applications & Properties” (NAP-2020)

Sumy, Ukraine, Nov. 9-13, 2020

03TFC01-1

Microstructure and Tribomechanical Properties of

WN-based Binary Multilayer Protective Coatings

Kateryna Smyrnova

Department of Nanoelectronics and

Surface Modification


Sumy, Ukraine [email protected]

Vyacheslav Beresnev

V.N. Karazin Kharkiv National

University

Kharkiv, Ukraine

Martin Kusý

Institute of Materials Science

Slovak University of Technology in

Bratislava

Trnava, Slovakia

Martin Sahul



Bratislava

Trnava, Slovakia [email protected]

Vyacheslav Stolbovoy

National Science Center

“Kharkiv Institute of Physics and

Technology”

Kharkiv, Ukraine

Marián Haršáni

Staton, s.r.o.

Turany, Slovakia

Alexander Pogrebnjak




Sumy, Ukraine

[email protected]

Ľubomír Čaplovič



Bratislava

Trnava, Slovakia

Recently, the economic and environmental aspects of various industries have been playing a vital role in their development strategies. Automotive, aerospace, and manufacturing industries produce every day a large number of products from small details and instruments to enormous cars and aircraft. The manufacturing process of all these items strongly depends on metals and their alloys, which is often expansive due to the increased supply risk of raw materials and harmful to the environment because of using different lubricants and coolants. Moreover, the fabrication of the products, such as various vehicles and tools, is followed by their exploitation that includes extreme operating conditions. That is one of the main reasons for the rapid wear and subsequent failure of the metals and alloys from which they are made. The solution that is successfully applied in practice is the deposition of the protective functional coating on the surface of the metal components, which prolongs their lifetime.

Nitride coatings with multilayer architecture are suitable candidates for the protection of metal details and tools due to their high mechanical and tribological characteristics. There are only a few papers on WN-based multilayer coatings, which were synthesized by different methods, and demonstrated that they worth attention for tribological applications [1-3].

Nanoscale multilayer WN-based coatings were deposited by cathodic arc evaporation using the Bulat-6 device. The WN and CrN or ZrN layers were alternately deposited on the steel substrates at the following parameters: substrate bias voltage Ub = -150 V, arc current Id = 100 A (WN)/100 A (MeN, where Me = Cr, Zr), working pressure in the vacuum chamber PN = 0.73 Pa, total deposition time t = 60 min. The elemental composition, cross-section morphology, and microstructure, mechanical properties, friction performance, and wear resistance of coatings were studied using scanning electron microscopy (SEM), wavelength-dispersive spectroscopy (EDS), X-ray diffraction (XRD), nanohardness testing, scratch and wear “ball-on-disk” tests.

According to the WDS analysis, the chemical composition of coatings is provided in Table 1. The W content was higher compared to Cr or Zr that resulted in thicker WN layers. The SEM images showed that WN/CrN and WN/ZrN coatings consisted of 14 nm- and 23.6 nm-thick bilayers, respectively.

TABLE I. ELEMENTAL COMPOSITION OF THE MULTILAYER WN/MEN

(ME = ZR AND CR) COATINGS

Element Concentration, at.%

WN/ZrN coating WN/CrN coating

W 26.4 37.3

Zr 21.2 -

Cr - 11.3

N 52.4 51.4

Total 100.0 100.0

The XRD analysis demonstrated that during the deposition process, the isostructural coatings with B1-NaCl face-centered cubic (fcc) structure was formed. The WN/CrN coating consisted of cubic W2N and CrN phases. Similarly, fcc W2N and ZrN phases were found in the sample with zirconium nitride. The hardness and reduced elastic modulus values for WN/CrN were 33.3 ± 2.5 GPa and 393.4 ± 37.8 GPa, and for WN/ZrN coating 37.3 ± 3.9 GPa and 438.8 ± 45.1 GPa, respectively.

REFERENCES

[1] F.-B. Wu, Sh.-K. Tien, J.-W. Lee, and J.-G. Duh, “Comparison in microstructure and mechanical properties of nanocomposite CrWN and nanolayered CrN/WN coatings,” Surf. Coat. Tech., vol. 200, pp. 3194-3198, 2006.

[2] Ju. Buchinger, N. Koutn, Zh. Chen, Z. Zhang P.H. Mayrhofer, D. Holec, et al., “Toughness enhancement in TiN/WN superlattice thin films,” Acta Mater., vol. 172, pp. 18-29, 2019.

[3] Ch.-L. Chang, Tz-H. Chiou, P.H. Chen, W.Ch. Chen, Ch.-T. Ho, and W.-Yu Wu, “Characteristics of TiN/W 2 N multilayers prepared using magnetron sputter deposition with dc and pulsed dc powers,” Surf. Coat. Tech., vol. 303, pp. 25-31, 2016.




03TFC02-1

Design of LPE Growth n+–i–n

+ GaAs Structures

with Submicron Layers for Gunn Diodes

Semen Krukovskyi

Department of Semiconductors

Structures

Scientific Research Company

“Electron-Carat”

Lviv, Ukraine [email protected]

Ihor Izhnin


Structures




Bogdan Prytulyak


Structures




Gunn diodes are an active elements used to generate electromagnetic waves in the millimetre range. To ensure the maximum power and frequency of HF generation, a constant voltage is applied between the cathode and the anode, which is several times higher than the threshold value. Therefore, the material of the active i–GaAs region of the diode should be characterized by high uniformity, low compensation and high electron mobility.

The requirements noted above determine the choice of basic technological methods and approaches that can be applied to achieve these parameters. Since the thickness of the active region in GaAs-based Gunn diodes is 1–2 µm, to achieve an uniformity electron concentration over the thickness it requires a formation of minimal transition regions at the interfaces between active i–GaAs and contact n

+-GaAs layers. From this point of view, the most universal

method is the low-temperature version of the liquid phase epitaxy (LPE) method [1], which provides a complex doping with rare earth (REE) and isovalent elements. REE have been tested in all known technological methods in order to improve the properties of the resulting epitaxial layers and structures, but the best results were achieved when they were use in the LPE method [2]. Unlike other technological methods, where the role of REE is reduced to gettering of uncontrolled impurities in the semiconductor matrix, in LPE the most uncontrolled impurities remain outside the semiconductor in the solution-melt in the form of compounds with REE, and only a small amount of REE atoms can get into the crystalline lattice, where they exhibit the properties of gettering centres [3, 4].

In this work, epitaxial structures of n+–i–n

+ GaAs layers

were grown from gallium melts in the temperature range 630-570 °C. High-purity gallium 6N grade (99.9999) was used as a solvent and n

+–GaAs (100) substrates from CMK

Ltd. (Slovakia) with a concentration of (1-5)∙1018

cm-3

.

To assess the uniformity of the electron concentration distribution in such structures, a high-resolution capacitive C-V profilometry was used. This technique, in addition to assessing the degree of homogeneity of doping over the layer thickness, also makes it possible to evaluate the sharpness of the profile of the electron concentration distribution at the interfaces between layers in the epitaxial structure. Electrochemical etching step through the epitaxial layer was controlled on the basis of the current-voltage characteristics of the electrolyte-semiconductor barrier using Accent PN4300PC profilometer. Aqueous solution of 0.2M

ethylenediamine (Sigma Aldrich, 98%) was used as an

electrolyte in electrochemical capacitance-voltage (ECV) profiling.

On the basis of the investigated profiles of the distribution of electrons concentration in the i–GaAs layers, it was shown that change of the concentration of the rare earth (Yb) and isovalent (Al) elements and their ratio in the melt solutions changes not only to the layer doping level, but also to the sharpness of the layer boundaries. In this case, however, the concentration of Yb in the melt should not exceed a certain critical value, above which its negative effect on the morphology of the layer surface appears.

The proposed technology made it possible obtaining epitaxial structures for Gunn diodes with low electron concentration of 1∙10

15 cm

-3 – 2∙10

16 cm

-3 and high mobility

of the order of 40000 cm2 / (V∙ s) at temperature 77K.

It is assumed that the most probable mechanism for the formation of the noted parameters of n

+–i–n

+ GaAs epitaxial

structures is a binding of predominantly donor uncontrolled impurities in the gallium melt by rare earth elements and a decrease in gallium vacancies concentration under the influence of isovalent aluminium.

Thus, it was shown that it is possible obtaining epitaxial structures for Gann diodes with a low electron concentration, high mobility and material homogeneity over the thickness of the active region using low-temperature liquid-phase epitaxy with complex doping with rare-earth and isovalent elements.

REFERENCES

[1] M. Milanova, V. Khvostikov, “Growth and doping of GaAs and AlGaAs layers by low-temperature liquid-phase epitaxy,” J. Cryst. Growth, vol. 219, pp. 193-198, 2000.

[2] O. Prochazkova, J. Zavadil, K Zdánský, “LPE InP layers grown in the presence of rare-earth elements,” Mater. Sci. Eng. B, vol. 80, pp. 14-17, 2001.

[3] R. Krukovskyi, Yu. Mykhashchuk, Ya. Kost, S. Krukovskyi, I. Saldan, “Weakly doped InP layers prepared by liquid phase epitaxy using a modulated cooling rate,” Phys. Scr., vol. 92, pp. 045701, 2017.

[4] R. Krukovskyi, H. Ilchuk, S. Krukovskyi, Rare-earth elements in the technology of obtaining epitaxial layers based on III-V materials, cken: LAP LAMBERT Academic Publishing, 2018.




03TFC03-1

Tailoring Magnetic Anisotropies in Thin Film

Structures Based on NixFe100-x Alloys

Christina Gritsenko

Immanuel Kant Baltic Federal University

Kaliningrad, Russia

[email protected]

Valeria Rodionova


Kaliningrad, Russia

[email protected]

Thin films of iron-nickel alloys are widely used to create magnetic field sensors, the properties of which, depending on the functional load, can put forward various requirements, including the presence of uniaxial magnetic anisotropy in the plane or perpendicular to the plane of the film, which, in modern technologies, is often achieved by energy-consuming or expensive methods. For example, additional expensive materials are used, such as Pt [1], [2]. At the same time, recent theoretical studies [3], [4] have shown that for thin films with thicknesses of a few nanometers, the deviation of the magnetization from the film plane is possible due to competition between shape anisotropy and magnetocrystalline anisotropy during the formation of a certain morphology of the film surface.

In this work, we studied both single NixFe100-x (x=40-80) thin films with thickness of 5 and 10 nm, and exchange biased structures, made by adding IrMn layer with different thicknesses of 2 50 nm. The samples were prepared by magnetron sputtering method onto Si substrate. Additional buffer and protective 30 nm of Ta layers were used in all samples.

It was found that the deposition of Ir45Mn55 layer onto the Ni40Fe60 layer causes a partial intermixing of the layers, while the deposition of Ir45Mn55 on the Ni75Fe25 layer makes the interface to be smooth. This tendency is explained by a difference in a grain size of NixFe100-x layers. A sequence of magnetization reversal for the two ferromagnetic layers in NixFe100-x/Ir45Mn55/NixFe100-x structures was found to depend on the NiFe composition and is determined by a competition between the ferromagnetic interlayer coupling and the interfacial exchange coupling.

ACKNOWLEDGEMENTS

This work was done in collaboration with Prof. Dr. Chechenin, N., Dzhun, I., Babaytsev, G., from Lomonosov Moscow State University (Moscow, Russia) and Dr. Volochaev from Federal Research Center KSC SB RAS (Krasnoyarsk, Russia).

REFERENCES

[1] S. Hirayama, S. Kasai, S. Mitani, “Interface perpendicular magnetic anisotropy in ultrathin Ta/NiFe/Pt layered structures,” Jpn. J. Appl. Phys., vol. 57, no 1, ID 013001, 2018.

[2] T. Nan, et al., “Comparison of spin-orbit torques and spin pumping across NiFe/Pt and NiFe/Cu/Pt interfaces,” Phys. Rev. B, vol. 91, no 21, ID 214416, 2015.

[3] O.A. Tretiakov, M. Morini, S. Vasylkevych, V. Slastikov, “Engineering Curvature-Induced Anisotropy in Thin Ferromagnetic Films,” Phys. Rev. Lett., vol. 119, no 7, ID 077203, 2017.

[4] M. Morini, V Slastikov, “Reduced Models for Ferromagnetic Thin Films with Periodic Surface Roughness,” J. Nonlinear Sci., vol. 28, pp. 513-542, 2018.




03TFC04-1

A New Combined Sputtering System for Complex

Nanostructured Coatings Synthesis

Alexander Zykov

School of Physics and Technology

V.N.Karazin Kharkiv National

University

Kharkiv, Ukraine [email protected]

Stanislav Dudin



University


Nina Yefimenko



University

Kharkiv, Ukraine

[email protected]

Stanislav Yakovin



University


Ion assisted magnetron deposition is a progressive way of nanostructured coatings deposition with high rates and improved properties compared with those made by a regular magnetron [1-3]. It is well known that the energy flux to the substrate surface is one of the key factors influencing the coating properties, and it consists of: 1) equilibrium heating of the sample, 2) non-equilibrium heating of the surface due to the relaxation of the kinetic energy of the ions, electrons and fast neutrals, 3) the energy of chemical reactions, and 4) the radiation energy flux [2]. In some of the papers the specific nonequilibrium energy per one deposited atom is proclaimed as the main factor determining the properties of the film. However, in recent years (see e.g. [4]), it has become clear that the situation is more complex. In particular, the energy deposition due to ion bombardment is defined by product of the ion energy and current density, but experiments show that the deposition result is dependent on each parameter independently rather than on their product.

This issue requires detailed study, but the most common technology of magnetron sputtering allows controlling only the ion energy by electrical biasing, while the ion current density remains constant at a constant deposition rate. Moreover, with direct current, this technicue can be used for conductive coatings only, while for dielectric coatings even the ion energy control is problematic. Thus, a tool is required allowing independent control of the flux ratio of sputtered atoms and energetic ions bombarding the growing film. It is highly desirable that this ability will be applicable to insulating materials.

In our previous papers [5, 6], the design and characteristics of combined magnetron-ion-source sputtering system (MISSS) were described. The system combines a magnetron and a Hall type ion source possessing common magnetic system. This allows to adjust the ion bombardment of the growing film controlling independently ion current density within the range of 0.1-10 mA/cm

2 and average ion

energy (300-1000 eV). MISSS provides deposition rate up to 3 nm/s at the gas pressure 0.5-10 mTorr. However, the system is not free from drawbacks: 1) the ion energy is appropriate for the surface cleaning but it is too high for the ion assistance of the film deposition, 2) the ion flow to the surface is hughly ingomogeneous.

In the present paper a new system is presented that is a further development of MISSS. The system combines a magnetron with an End-Hall ion source providing ion current density of 0.1-5 mA/cm

2 and average ion energy of 30-300

eV. This energy range is most effective just for the film growth control without significant sputtering. Similarly to [4] this device uses the magnetron for deposition and the End-Hall ion source for ion assist, but in contrast, our system is axially symmetrical providing high homogeneity of processing. The uniqueness of this apparatus results from the use of electrons from the magnetron discharge for ionization in the ion source and for the ion beam neutralization without an external source of electrons. We present the discharge characteristics of this system depending on gas pressure, magnetic field magnitude, both for autonomous and for joint operation of the magnetron discharge and the ion source. It is demonstrated, that this new deposition system is suitable for high-rate reactive synthesis of complex nanostructured coatings. The unique feature of the system is that it generates the bipolar flow of ions and electrons towards the treated surface with the ability to regulate their ratio over a wide range. In particular, the generation of a quasi-neutral flux is possible, enables dielectric film deposition with high-energy ion bombardment using direct current.

REFERENCES

[1] J.A. Thornton, “Substrate heating in cylindrical magnetron sputtering sources,” Thin Solid Films, vol. 54, no 1, pp. 23-31, 1978.

[2] J. Musil, “Hard nanocomposite coatings: Thermal stability, oxidation resistance and toughness,” Surf. Coat. Technol., vol. 207, pp. 50-65, 2012.

[3] V. Zhurin, Industrial Ion Sources, Wiley-VCH Verlag & Co. KGaA, 2012.

[4] A.-L. Thomann et al., “Energy flux measurements during magnetron sputter deposition processes,” Surf. Coat. Technol., vol. 377, p. 124887, 2019.

[5] S. Dudin et al., “Design and research of combined magnetron-ion-beam sputtering system,” Probl. At. Sci. Technol.. Series: Plasma Physics, vol. 118, no 6, pp. 263-266, 2018.

[6] A. Zykov et al., “Combined Magnetron-Ion-Source System for Reactive Synthesis of Complex Nanostructured Coatings,” In: Pogrebnjak A., Bondar O. (eds) Microstructure and Properties of Micro- and Nanoscale Materials, Films, and Coatings (NAP 2019). Springer Proceedings in Physics, vol 240, Springer, Singapore, 2020, pp. 161-175.




03TFC05-1

New Type of Superhard Nanocomposite Coatings

on the Basis Nanostructured AlTiN and

Diamond-Like Coatings - Orientant

Lin Changhong, Puyou Ying, Min Huang, Jianbo Wu, Zhang Ping, Yang Tao, Vladimir Levchenko

Taizhou University China

The given work brief report on the history synthesis of new type nanocomposite with carbon materials not having analogues in the world, which provides essential reducing of power losses in lubricated tribounits. Efficiency of these new carbon materials is based on the established by the authors of the work fact that the carbon coatings with monocrystalline or polycrystalline highly ordered structures and linear chains of carbon increase essentially the level of molecular ordering in lubricating boundary layers and ensure adsorption of boundary layers on the coatings. Boundary layers repeat highly ordering structure present by surface of the coating what results in lubricating ability improving, boundary layers’ thermal stabilization, extending the ranges of

operating temperatures of oils, etc. Besides, using the mentioned coatings allows lowering the number of additives in lube oils. A new type of superhard materials of diamond like carbon (DLC) with monocrystalline structure namely nanostructured coating-orientants and PVD process is developed to produce nanocomposite (DLC + AlTiN) coating on any metal or ceramic substrates. The new type of the functional materials has no analogues in triboengineering. The findings suggest that the nanocomposite coatings with orientating effect on boundary layers are advantageous for improving antifriction characteristics and for governing processes of boundary lubrication.




03TFC06-1

Surface Modifications of Detonation Nanodiamonds

J.C. Arnault

NIMBE UMR CEA-CNRS 3685, Paris Saclay University, Gif sur Yvette, France

Since the last ten years, nanodiamonds (ND) underwent a growing interest from researchers, engineers and companies. At the nanoscale, diamond still retains most of its outstanding mechanical, chemical, electronic, thermal, optical and biological properties. Combining these assets, ND are currently investigated for nanomedicine and bioapplications, quantum technologies, catalysis and energy applications, advanced composites and lubricants.

For these applications, the surface chemistry of ND plays a major role and strongly governs ND properties. Like bulk diamond, nanodiamonds behave a versatile surface chemistry [1].

During this talk, different surface modifications of detonation ND performed in our laboratory will be presented using either thermal or plasma treatments. Chemico-physical characterizations and specific properties of hydrogenated, oxidized and graphitized detonation ND will be discussed. Potential applications will be exposed from photocatalysis to bioapplications.

REFERENCES

[1] A. Krueger, Current issues and challenges in surface chemistry of nanodiamonds in “Nanodiamonds: Advanced Material Analysis, Properties and Applications”, Elsevier, 2017, 183, J.-C. Arnault (Ed.)




03TFC07-1

Multilayer and High-Entropy Alloy-Based Coatings

for Solving the Critical Raw Materials Problem

Bogdan Postolnyi

Sumy State University, Sumy, Ukraine

IFIMUP, University of Porto, Porto,

Portugal [email protected]

João Pedro Araújo

The Institute of Physics for Advanced

Materials, Nanotechnology and

Photonics (IFIMUP)

Faculty of Sciences, University of Porto

Porto, Portugal

Vladimir Buranich




Sumy, Ukraine

Alexander Pogrebnjak




Sumy, Ukraine

Kateryna Smyrnova




Sumy, Ukraine

Vladyslav Rogoz




Sumy, Ukraine

By the European Commission, the critical raw materials are defined as raw materials of high importance to the economy of the EU and whose supply is associated with high risk [14]. Schematically it is explained in Fig. 1. According to the communication from the European Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions in 2017 [15] the Critical Raw Materials List consists of 27 raw materials and groups.

Fig. 1. Vulnerability plot from 2014 EC-report on critical materials. As

taken from [1].

The problem of CRMs must be mitigated by at leas three differen scientific approaches: (1) improving the production processes of CRMs (increasing sustainable extraction, reducing extraction costs, increasing the efficiency of materials, increasing security, etc); (2) finding suitable candidates to partially or totally substitute the CRMs; (3) increasing their recycling.

Cemented carbide is one of the most popular cutting tool material. Typically a carbide cutting tool is manufactured with a mixture of tungsten and cobalt (the binder that holds the tungsten carbide together), with wealth of variations in carbide grain size and ratio of carbide to binder.

The aforementioned two important ingredients of the carbide tooling, namely, tungsten and cobalt were earlier identified (in 2011) among the list of the 14 critical raw materials vital to the EU industries. More recently, in 2014 and in 2017, they have continued to remain on this list on account of their economic importance and risk of supply interruption (see Fig. 2).

Fig. 2. Critical raw materials list for 2011–2017 overlaid on the periodic

table of the elements. Adapted from [2].

Protective coatings may significantly increase the life time of tools and, thus, reduce consumption of CRMs content in bulk materials. The coated cutting tools may have extra lifetime of 200-500 % and more with the same cutting velocities. These also can lead to the increase of operational velocities (by 50 to 150 %) for the same lifetime of cutting tools. Furthermore, most of the modern coatings are CRM-free.

REFERENCES

[1] European Commission, Deloitte Sustainability, British Geological Survey, Bureau de Recherches Géologiques et Minières, Netherlands Organisation for Applied Scientific Research. European Commission Final Report: Study on the review of the list of critical raw materials. Brussels: 2017.

[2] A. Rizzo, S. Goel, M.L. Grilli, R. Iglesias, L. Jaworska, V. Lapkovskis, et al., “The Critical Raw Materials in Cutting Tools for Machining Applications: A Review,” Materials (Basel), vol. 13, ID 1377, 2020.




03NP01-1

Integration of Plasmonic and Si Nanophotonics

Devices Vadym Zayets

Research Institute for Advanced

Electronics and Photonics National

Institute of Advanced Industrial Science

and Technology (AIST)

Tsukuba, Japan

[email protected]

Benefit of plasmonic devicies integrated with Si nanowire waveguides are a compact size, an ultrahigh speed and technoligical compatibility with fabrication technology of the Photonic Integrated Curcuits (PIC). For example, the opreation speed larger than 70 GB/s was experimentally demonstrated with a plasmonic molator having length as

short as 10 m [1].

Optical isolator is an important element of optical networks. It protects optical elements from unwanted back reflection. The optical isolator is one of a few optical components, which has not yet been integrated into commercial PIC. A plasmonic isolator [2-4] is a promising candidate for such integration. Figure 1 shows a design of the plasmonic isolator. It consists of a nanowire waveguide,

small part of which (about 2-16 m) is etched out, and a ferromagnetic metal is deposited in the gap. The cobalt is not transparent and the light propagation from input waveguide to output waveguide is blocked by the Co. However, a surface plasmon is excited at Co-TiO2/SiO2 interface and light can reach from the input fiber to output fiber. The Co is magneto-optical material and its optical properties are non-reciprocal. It means that they are different for two opposite directions of light propagation. The plasmonic waveguide containing the Co is optimized so that a plasmon is excited in one direction, but a plasmon cannot be excited in the opposite direction. Therefore, light can pass from input to output only in forward direction, but light is blocked in the opposite direction.

Fig. 1. Integration of a Co/TiO2/SiO2 plasmonic waveguide with a Si

nanowire waveguide

The propagation loss is unavoidable for a surface plasmon. In the data-processing devices a low insertion optical loss is a critical parameter and the surface plasmons with the smallest propagation loss should be used [1]. We have developed a fabrication technology for an integrated plasmonic devices of a very low propagation loss and

moderate coupling efficiency with a Si nanowire waveguide. Figure 2 shows the fiber-to-fiber transmission as function of wavelength for different lengths of the Co/TiO2/SiO2 bridge-type plasmonic waveguide [2] integrated with a Si nanowire waveguide (See Fig. 1). The black line shows the case of Si waveguide without plasmonic section. The 10 dB correspond to fiber-waveguide-fiber coupling loss. The red line shows the case of the shortest length of plasmonic section. In this case, the propagation loss can be ignored and the loss is only due to the coupling loss. From additional loss due to elongation of the plasmonic section, the plasmon’ propagation loss is calculated. The propagation loss is 0.7

dB/m and it is nearly independent on wavelength. The coupling loss between plasmonic and Si nanowire waveguides is 4 dB per a facet.

The achievement of a small propagation loss of a surface plasmon on Si and a moderate coupling efficiency between a plasmonic and Si nanowire waveguide demonstrates a feasibility of the integration of plasmonic devices (plasmonic isolator and plasmonic modulator) into a commercial PIC.

Fig.2 Fiber-to-fiber transmission as function of wavelength for different lengths of Co/TiO2/SiO2 bridge-type plasmonic waveguide integrated with Si nanowire waveguide [2].

REFERENCES

[1] C. Haffner, et al., “All-plasmonic Mach-Zehnder modulator enabling optical high-speed communication at the microscale,” Nat. Photonics, vol. 9, no. 8, pp. 525-528, 2015.

[2] H. Shimizu, V. Zayets, “Plasmonic isolator for photonic integrated circuits,” MRS Bull., vol. 43, no. 6, pp. 425-429, 2018.

[3] V. Zayets, H. Saito, K. Ando, S. Yuasa, “Long-distance propagation of a surface plasmon on the surface of a ferromagnetic metal,” Opt. Express, vol. 23, no. 10, pp. 12834-12839, 2015.

[4] V. Zayets, H. Saito, S. Yuasa, K. Ando, “Enhancement of the transverse non-reciprocal magneto-optical effect,” J. Appl. Phys., vol. 111, no. 2, ID 023103, 2012.




03NP02-1

Luminescence Properties of Magnesium Aluminum

Spinel in Nanocrystalline and Single-crystal States

with Cr-impurities Karina Lamonova

Department of Theory of Dynamic

Properties of Complex Systems

O.O.Galkin Donetsk Institute for

Physics and Engineering of NASU

Kharkiv, Ukraine

[email protected]

Sergii Orel





Kharkiv, Ukraine

[email protected]

Igor Danilenko

Department of Physical Materials

Science O.O.Galkin Donetsk Institute

for Physics and Engineering of NASU


Yurii Pashkevich





Kharkiv, Ukraine

[email protected]

Yurii Kazarinov

Physics Department

V.N. Karazin Kharkiv National

University

Kharkiv, Ukraine

NSC Kharkiv Institute of Physics and

Technology


We report the correlation between the structural and luminescence properties of the MgAl2O4 spinel that contains chromium impurities. Magnesium aluminate spinel is an inexpensive perspective host material for phosphors due to its stability in a wide range of temperatures, high chemical resistance, mechanical strength, wide band gap (6.8 eV), and excellent dielectric and optical properties.

Phosphors' optical properties based on spinels in the nanocrystalline state is expected to amplify in comparison with a single crystal's, the production of which is much more expensive than the making of nanocrystalline samples. Therefore the problem related to the impact of the local structure around activation centers on their electronic structure is in demand in terms of the technological applications in optics-related fields.

In this context, we synthesized polycrystalline samples of MgAl2O4 at 700ºC and 1000ºC by the inverse co-precipitation method. The X-ray analysis indicates that the initial structure of the powder is amorphous to at least 700°C. The nanoparticles in the sample synthesized at 1000°C manifest a spinel crystal structure with an average size of about 15 nm and the lattice parameter of 8.06685±0.0042 Å. That is less of 0.2% than the 700ºC one has.

We examined excitation (fig. 1a) and emission (fig. 1b) spectra of luminescence for the nanocrystalline MgAl2O4 samples and compared them with the corresponding spectra of the MgAl2O4 single crystal. It was revealed that all the samples of interest contain uncontrolled chromium impurities, which manifest a characteristic luminescence signal in the range of 640–740 nm.

A comparison of the emission spectra obtained from the nanocrystalline samples and the single crystal indicates that the structure of the 700°C-sample is more disordered than the 1000°C one has. That's because the particle sizes in the 700°C-sample are smaller, and, hence, the ratio of the surface area to the particle volume is higher than 1000°-sample has.

Fig. 1. The luminescence excitation (а) and the luminescence emission (b)

spectra in the MgAl2O4 single crystal and in the nanocrystlline samples of

magnesium aluminate spinel synthesized at 700°С and 1000°С. The exitation wavelength is λex = 560 nm; λem = 688 nm is the maximum Cr3+

emission wavelength which corresponds 2Eg→4A2g transition.

To simulate the obtained luminescence spectra from a theoretical standpoint, we have applied the Modified Crystal Field Theory [1].

REFERENCES

[1] K.V. Lamonova, S.M. Orel, Yu.G. Pashkevich, Modified Crystal Field Theory and its Applications, Kyiv: Akademperiodyka, 2019.

300 350 400 450 500 550 600 6500

10

20

30

40

50

60(a)

Inte

nsi

ty,

arb

.un

.

Wavelength, nm

MgAl2O

4 (T = 1000°C)

MgAl2O

4:Cr single crystal

em

= 688 nm

640 660 680 700 720 7400

4

8

12

16

20

24 ex

= 560 nm(b)

MgAl2O

4 (T = 700°C)

MgAl2O

4 (T = 1000°C)

MgAl2O

4:Cr single crystal

Inte

nsi

ty,

arb

.un

.

Wavelength, nm




03NMM01-1

Thermally-induced Structural Phase Transitions in

Pt/Fe Layered Stacks with Additional Layers of

Alloying Elements

Ivan Kruhlov

Physics of Metals Department

Igor Sikorsky KPI

Kyiv, Ukraine [email protected]

Gabor Katona

Department of Solid State Physics

University of Debrecen

Debrecen, Hungary

[email protected]

Oksana Shamis


Igor Sikorsky KPI


Manfred Albrecht

Institute of Physics

University of Augsburg

Augsburg, Germany

[email protected]

augsburg.de

Nataliia Schmidt

Institute of Physics

University of Augsburg

Augsburg, Germany

[email protected]

Igor Vladymyrskyi


Igor Sikorsky KPI

Kyiv, Ukraine

[email protected]

Structural phase formation in layered stacks induced by thermally-activated diffusion processes is a promising reaction pathway for the synthesis of novel thin film materials. It should be taken into account that the sequence of phase transitions during annealing of thin metallic layers can substantially vary from those predicted by corresponding bulk phase diagrams due to the underlying grain boundary diffusion mechanisms, surface and interface effects and corresponding deviation from equilibrium.

Thin films based on FePt alloy are considered to be one of the most promising magnetic materials for various applications in nanoscale devices regarding to its high value of magneto-crystalline anisotropy (Ku = 7 MJ/m

3) of the

chemically ordered L10-FePt phase. For instance, L10-FePt phase could be formed by post-annealing of Pt/Fe bilayers at relatively low-temperatures, which ensure diffusion processes limited to grain boundary mechanisms [1]. Furthermore, introduction of additional intermediate layers into Pt/Fe stacks could modify significantly the phase transition temperatures [2], the sequence of structural transitions that occur upon annealing [3], or even induce metastable phases [4].

In present study, the sequence of phase transitions occurring in bi-layered stack of Pt/Fe as well as in the films with additional intermediate layers, either forming ternary alloys (Mn) or show non-miscibility (Tb) during post-annealing up to 620 °C in vacuum (10

-3 Pa) was explored by

a combination of x-ray diffraction, transmission electron microscopy, chemical depth profiling, atomic force microscopy, electrical resistivity probing and SQUID magnetometry.

It was found, that grain boundary diffusion sets in about 150 °C in Pt/Fe bilayer. Further increase of the annealing temperature leads initially to the formation of the disordered A1-FePt phase along with a small fraction of L10 ordered grains. The later becomes the dominant phase upon further annealing. Eventually, a full intermixing with the presence of a homogeneous L10-FePt phase is achieved at 620 °C. Moreover, it was concluded that measurement of electrical resistivity during the heating of Pt/Fe bilayer provides valuable information on diffusion processes, structural phase

formations and its stability range, as well as on the magnetic transition temperature.

Simultaneously, the introduction of additional intermediate layers into Pt/Fe stack substantially affects its phase composition upon annealing.

In particular, heat treatment of Pt/Mn/Fe trilayer initially leads to the L10-MnPt phase formation within 280 °C – 450 °C followed by the formation of metastable bcc Fe3Pt, which gets further transformed to fcc Fe3Pt and eventually to chemically ordered L12-Fe3Pt. Besides, a pronounced Mn surface segregation with formation of oxide phase is registered. The final product after annealing at 620 °C consists of two interesting phases, which are relevant for spintronic applications: antiferromagnetic L10-MnPt with addition of Fe and ferromagnetic L12-Fe3Pt.

In turn, the post-annealing of Pt/Tb/Fe trilayer leads to the diffusive formation of binary Pt2Tb phase at 215 °C, followed by the appearance of the chemically disordered A1-FePt phase at 280 °C. Eventually, the final phase product at 620 °C is characterized by the coexistence of two remaining phases, L10-FePt and TbO2. It is noteworthy that structural phase transitions in this case have a significant impact on the films magnetic properties – heat treatment leads to an enhancement of the coercive field due to grain isolation induced by Tb/Tb-O grain boundary filling.

REFERENCES

[1] G.L. Katona, I.A. Vladymyrskyi, I.M. Makogon, S.I. Sidorenko, F. Kristály, L. Daróczi, A. Csik, A. Liebig, G. Beddies, M. Albrecht and D.L. Beke, “Grain boundary diffusion induced reaction layer formation in Fe/Pt thin films,” Appl. Phys. A, vol. 115, pp 203-211, 2014.

[2] Y.S. Yu, Hai-Bo Li, W.L. Li, Mei Liu and W.D. Fei, “Low-temperature ordering of L10 FePt phase in FePt thin film with AgCu underlayer,” J. Magn. Magn. Mater., vol. 320, pp. L125-L128, 2008.

[3] R. Gupta, R. Medwal, P. Sharma, A.K. Mahapatro, S. Annapoorni, “Effect of Pt layers on chemical ordering in FePt thin films,” Superlattice. Microst., vol. 64, pp. 408-417, 2013.

[4] G.L. Katona, N.Y. Safonova, F. Ganss, D. Mitin, I.A. Vladymyrskyi, S.I. Sidorenko, I.N. Makogon, G. Beddies, M. Albrecht, D.L. Beke, “Diffusion and solid state reactions in Fe/Ag/Pt and FePt/Ag thin-film systems,” J. Phys. D: Appl. Phys., vol. 48, ID 175001, 2015.




03NMM02-1

Theory of Three-magnon Scattering in Vortex-state

Magnetic Nanodisks

Roman Verba

Institute of Magnetism

Kyiv, Ukraine

[email protected]

Vasyl Tyberkevych

Department of Physics

Oakland University

Rochester, MI, USA

Andrei Slavin


Oakland University Rochester, MI, USA

Spin waves in ferromagnetic micro- and nanostructures demonstrate a great variety of nonlinear phenomena at moderate excitation power, which allows to build various nonlinear signal processing and microwave devices [1,2]. In particular, 3-magnon scattering is used in frequency-selective power limiters [3], excitation of highly nonuniform modes, which are not accessible by direct excitation [4], etc.

Although 3-magnon interaction in thin bulk samples and films is well-studied [2], the results of these numerous studies cannot be translated to magnetic micro- and nanostructures. First, spatial confinement results in the discreteness of spin wave spectrum, so that resonant multi-magnon processes could become impossible and, instead, nonresonant nonlinear scattering takes place. Second, nonuniform distribution of static magnetization and complex profiles of spin-wave eigenmodes lead to selection rules and features of the scattering, specific for a certain magnetic structure.

In this work, we consider 3-magnon interaction in a magnetic disk excisting in a vortex state, which is a ground state of thin magnetic disks with diameters ranging form 100 nm to tens of microns. Using vector Hamiltonian formalism [5], we derived general expressions for the interaction efficiency between arbitrary three eigenmodes of a vortex. It is found, that 3-magnon spitting of spin-wave mode (n3, m3) into modes (n1, m2) and (n2, m2) obeys following selection rules: conservation of azimuthal number m3 = m1 + m2, and, for radially symmetric mode (m3=0),

inequality of radial number of split modes, n1 ≠ n2. The last

rule, however, is relaxed in small dots due to increasing role of the vortex core, which, also, lifts the degeneracy of spin-wave modes with opposite azimuthal numbers ±m. In total, the splitting always goes into a pair of frequency nondegenerated modes.

3-magnon interaction efficiency V12,3 significantly depends on the split modes, as exemplary shown in Fig, 1(b) for the splitting of second radial (2,0) mode of vortex-state permalloy disk (50 nm thickness, 5 μm diameter). Due to quite dense spectrum, the resonance condition for 3-magnon splitting is almost satisfied for several pairs of split modes, as shown by arrows. Therefore, the dependence of V12,3 becomes crucial in the determination of actual split modes. In this case larger efficiency V12,3 determines splitting into (0,5)+(2,-5) modes, in full accordance with experimental data [4]. Varying the driving frequency, the split spin-wave branches can be changed, e.g. to (1,m)+(2,-m) at 8.9-9 GHz. Thus, the developed theory allows to predict splitting channel and splitting threshold, as well as is useful for the investigation of stimulated sub-threshold 3-magnon processes in magnetic vortices.

Fig. 1. (a) Spin-wave spectrum of the considered vortex-state disk

(calculation); dashed arrows show possible splitting channels,

which are close to the three-magnon splitting

resonance condition at the excitation frequency of 8.3 GHz. (b)

Three-wave interaction efficiency of the radial mode

(2, 0) with different pairs of azimuthal SW modes.

This work was partially supported by National Academy of Sciences of Ukraine (agreement No. 23-04/01-2020)

REFERENCES

[1] G. Bertotti, I. Mayergoyz, C. Serpico, Nonlinear Magnetization Dynamics in Nanosystems, Elsevier: Oxford, 2009.

[2] V.S. L’vov, Wave Turbulence under Parametric Excitation, Springer-Verlag: New York, 1994.

[3] A.D. Boardman, S.A. Nikitov, “Three- and four-magnon decay of nonlinear surface magnetostatic waves in thin ferromagnetic films,” Phys. Rev. B, vol. 38, ID 11444, 1988.

[4] K. Schultheiss, R. Verba, F. Wehrmann, K. Wagner, L. Korber, T. Hula, et al., “Excitation of whispering gallery magnons in a magnetic vortex,” Phys. Rev. Lett., vol. 122, ID 097202, 2019.

[5] O. Dzyapko, I. Lisenkov, P. Nowik-Boltyk, V.E. Demidov, S.O. Demokritov, et al., “Magnon-magnon interactions in a room-temperature magnonic Bose-Einstein condensate,” Phys. Rev. B, vol. 96, ID 064438, 2017.




03NMM03-1

Spintronic Devices for Efficient Computing

A. Hirohata, K. Elphick,

W. Frost, E. Jackson,

M. Samiepour

Department of Electronic

Engineering, University of

York United Kingdom

T. Seki, T. Kubota,

D. Takano, R. Ramos,

E. Saitoh, K. Takanashi

Institute for Materials

Research, Tohoku University

Japan

T. Tsuchiya, T. Ichinose,

S. Mizukami Advanced Institute for

Materials Research,

Tohoku University

Japan

E. Saitoh

Department of Applied

Physics, University of

Tokyo Japan

Since the development of magnetic random access memory using spin-transfer torque reached its commercialisation phase, spintronics has entered a new era. For further improvement and implementation of spintronic devices, a new ferromagnetic material with a small damping constant below 0.001 and 100% spin polarisation is required to be developed in a film form at room temperature [1,2]. Especially, Heusler alloys have been attracting intensive attention to satisfy these requirements by crystallising it into a perfectly ordered phase but at high temperature, typically above 400°C [3]. We have recently developed a new process to reduce the crystallisation temperature down to 80°C for a Heusler alloy film grown on a (110)-oriented seed layer [4], which is compatible with the current memory fabrication process.

Giant magnetoresistive junctions consisting of a Heusler alloy, Co2FeAl0.5Si0.5/Ag/Co2FeAl0.5Si0.5, were grown by ultrahigh vacuum sputtering. They show only a small resistance change but their structures can be optimised further. For highly efficient operation, the corresponding switching current density was demonstrated to be controlled by replacing oxide insulating layers to isolate top and bottom electrodes by a ferromagnetic oxide layer to induce spin wave to assist the current-induced magnetisation switching.

These junctions were also characterised by non-destructive imaging to observe the quality of the buried junction interfaces with scanning electron microscopy we developed recently [5]. We managed to improve the yield of such junctions by 15% by identifying the cause of damages with our imaging technique. Additionally, this technique was applied to magnetic tunnel junctions for the improvement of their properties. These results pave a way for further improvement of the spintronic devices.

This work was supported by Seagate Technology, EPSRC-JSPS Core-to-Core Programme (EP/M02458X/1) and JST CREST Project (No. JPMJCR17J5).

REFERENCES

[1] A. Hirohata, K. Takanashi, “Future Perspectives for Spintronic Devices,” J. Phys. D: Appl. Phys., vol. 47, ID 193001, 2014.

[2] A. Hirohata, et al., “Review on Spintronics: Principles and Device Applications,” J. Magn. Magn. Mater., vol. 509, ID 166711, 2020.

[3] C. Felser, A. Hirohata (Eds.), Heusler Alloys, Springer, Berlin, Germany, 2016.

[4] W. Frost et al., “Low-temperature crystallisation of Heusler alloy films with perpendicular magnetic anisotropy,” J. Magn. Magn. Mater., vol. 484, pp. 100-104, 2019.

[5] E. Jackson, et al., “Chemical and structural analysis on magnetic tunnel junctions using a decelerated scanning electron beam,” Sci. Rep., vol. 8, ID 7585, 2018.




03NMM04-1

Magnetic Properties of Heavily Cr+-implanted CdTe

Single Crystals with Dopant-related Nanoclusters

Volodymyr D. Popovych

Off-Campus Faculty of Engineering

and Technical Sciences in Stalowa

Wola

The John Paul II Catholic University of

Lublin

Stalowa Wola, Poland

Department of Technological and

Professional Education

Ivan Franko Drogobych State

Pedagogical University,

Drogobych, Ukraine [email protected]

Shengqiang Zhou

Institute of Ion Beam Physics and

Materials Research

Helmholtz-Zentrum Dresden-

Rossendorf

Dresden, Germany

[email protected]

Antoni Żywczak

Academic Center for Materials and

Nanotechnology

AGH University of Science and

Technology

Krakow, Poland [email protected]

Bogumil Cieniek

Institute of Physics, College of Natural

Sciences

University of Rzeszow

Rzeszow, Poland [email protected]

Ireneusz Stefaniuk


Sciences



Roman Böttger

Institute of Ion Beam Physics and

Materials Research

Helmholtz-Zentrum Dresden-

Rossendorf

Dresden, Germany [email protected]

Marian Kuzma


Sciences



Cd1-xCrxTe was theoretically predicted to be a very

perspective material for spintronic applications. However, heavy doping is strongly limited by poor solubility of Cr in II-VI compounds, which leads to its precipitation [1]. In order to overcome this inherent obtacle, ion implantation was applied as a non-equilibrium doping technique. The samples for investigations were prepared from the vapour grown CdTe:I (concentrations NI = 10

18 and 10

19 cm

-3) single

crystals, implanted at high vacuum by 500 keV Cr+ ions with

fluences from 1016

to 51017

cm-2

[2]. Their magnetic properties were studied both by magnetization measurements and by EPR method.

Clear hysteresis loops were recorded not only at LN but also at RT indicating the magnetic ordering in the investigated material (Fig.1). The temperature dependences of the magnetization at FC and ZFC revealed super-paramagnetic behavior of the samples.

Fig. 1. Magnetic field dependences of the magnetization for Cr-implanted

CdTe:I (NI = 1019 cm-3) sample (ion fluence 51017 cm-2) at LN and RT.

EPR spectrum at RT consists of two components (Fig.2). A very broad line at higher field is attributed to the spins of the conduction electrons and it disappears at low temperatures due to decrease of free carrier concentration.

Computer fitting revealed that a line at lower field is of Callen shape below 160 K, and it is associated with a super-paramagnetic state of Cr-related nanoclusters, formed in the samples during their implantation [2]. A hyperfine structure at low temperatures is induced by spins of iodine nucleons.

Fig. 1. EPR spectra of the same sample as in Fig. 1.

It can be concluded that the magnetism of CdTe single crystals, heavily implanted with Cr

+ ions, is mainly

originated from nano-sized dopant-related second particles, although contribution from diluted magnetic Cd1-xCrxTe phase is also presented.

REFERENCES

[1] V.D. Popovych, P. Sagan, M. Bester, B. Cieniek, and M. Kuzma, “Structural and compositional investigations of vapour grown CdTe:Cr single crystals,” J. Cryst. Growth, vol. 426, no 1, pp. 173-179, 2015.

[2] V.D. Popovych, R. Böttger, R. Heller, Sh. Zhou, M. Bester, B. Cieniek, R. Mroczka, R. Lopucki, P. Sagan, M. Kuzma, “Heavy doping of CdTe single crystals by Cr ion implantation,” Nucl. Meth. Phys. Res. B, vol. 419, pp. 26-31, 2018.

mailto:[email protected]




03NMM05-1

Handling of Magnetic Properties of Ferromagnetic

Micro Scale Materials with Curvy Geometry

Valeria Kolesnikova, Valeria

Rodionova

Immanuel Kant Baltic Federal

University

Kaliningrad, Russia

[email protected]

Nikolai Andreev, Andrei Bazlov

National University of Science and

Technology «MISIS»

Moscow, Russia

Montserrat Rivas

Department of Physics, University of

Oviedo

Gijón, Spain

Ferromagnetic micro-scale materials with curvy geometry with their advantages of the stress and size find applications in security control and coding systems, sensitive sensors of magnetic fields, mechanical stresses, temperatures, deformation, induction systems in microelectronics and medical applications [1,2]. Well known examples of curvy micro scale magnetic materials – are ferromagnetic microwires with the amorphous metallic nucleus. The development of complex nanocrystalline alloys from their metastable amorphous precursors became the state-of-art topic in creating new materials for high-temperature applications [3,4]. The methods of partial or directional crystallization by heat treatments are used to reach hard magnetic properties, required for μ-magnets applications [5]. This work offers a novel way of studying the magnetic properties of ferromagnetic micro scale materials with curvy geometry which consist of nanocrystallites embedded in an amorphous matrix without an additional step of annealing the amorphous precursor. In this work, the magnetic and structural properties of Fe, FeCo and Co-based microwires were studied.

The structural changes in the nucleus directly affect the magnetic properties and uniquely on each composition. Structural features were studied using XRD and TEM analyses, which allowed us to determine the phase composition shape, and size of the formed crystallites. In the course of the analysis by the method of differential scanning calorimetry, conclusions were drawn about the complex process of recrystallization during thermal heating to 700 ° C. A two-step process is typical for microwires made of Fe-based alloy, a three-step process for FeCo-based, and a one-step process for Co-based magnetic materials. Using the modified thermogravimetric analysis in the presence of an external constant magnetic field, it was revealed that the recrystallization process is accompanied by a change in the magnetic order in several stages, which corresponds to the formation of new crystalline phases during heating.

The integral magnetic properties of microwires were studied via a vibration magnetometer (VSM). The relationship between the influence of the structure and magnetic properties was investigated by FORC-analysis (First Order Reversal Curve) via VSM. This method made it possible to determine two positively interacting magnetic phases for Co-based microwires. But for FeCo-based microwires, the magnetic interaction, obtained by FORC-diagram is more complex, which is interpreted as the presence of competing for magnetic phases of different compositions.

Thus, the result of this work leads to the creation of a new model of “structure properties – magnetic properties” dependence for ferromagnetic micro-scale materials with curvy geometry for industry and biomedicine applications.

REFERENCES

[1] A. Uddin, F.X. Qin, D. Estevez, S.D. Jiang, L. V Panina, H.X. Peng, “Microwave programmable response of Co-based microwire polymer

composites through wire microstructure and arrangement

optimization,” Compos. Part B, vol. 176, ID 107190, 2019. [2] C. Morón, C. Cabrera, A. Morón, A. García, M. González, “Magnetic

sensors based on amorphous ferromagnetic materials: A review,”

Sensors (Switzerland), vol. 15, pp. 28340-28366, 2015. [3] N. Zhou, T. Hu, J. Huang, J. Luo, “Stabilization of nanocrystalline

alloys at high temperatures via utilizing high-entropy grain boundary

complexions,” Scr. Mater., vol. 124, pp. 160-163, 2016. [4] A. Zhukov, M. Ipatov, M. Churyukanova, A. Talaat, J.M. Blanco,

V. Zhukova, “Trends in optimization of giant magnetoimpedance

effect in amorphous and nanocrystalline materials,” J. Alloy. Compd., vol. 727, pp. 887-901, 2017.

[5] K. Hoshino, Y.Y. Huang, N. Lane, M. Huebschman, J.W. Uhr, E.P. Frenkel, X. Zhang, “Microchip-based immunomagnetic detection of circulating tumor cells,” Lab Chip., vol. 11, vol. 3449-3457, 2011.




03NMM06-1

A Cluster-glass Behavior of Co2+

-containing

Layered Double Hydroxide Intercalated with Nitrate

Alexey Fedorchenko, Elena Fertman

ILTPE - B.Verkin Institute for Low

Temperature Physics & Engeneering of

NAS of Ukraine


Erik Čižmár, Alexander Feher

Institute of Physics, Faculty of Science,

P.J. Šafárik University

Košice, Slovakia

[email protected]

Vasili V. Rubanik Jr, Vasili V. Rubanik

Institute of Technical Acoustics of NAS

of Belarus,

Vitebsk, Belarus

[email protected]

Daniel E.L. Vieira, Andrei N. Salak

Department of Materials and Ceramics

Engineering and CICECO-Aveiro

InstItute of Materials,

University of Aveiro Aveiro, Portugal

[email protected]

Yurii Pashkevich, Roman Babkin



O. O. Galkin Donetsk Institute for

Physics and Engineering of NAS of

Ukraine

Kharkiv-Kyiv, Ukraine

[email protected]

Layered double hydroxides (LDHs) consist of the alternating positively-charged mixed metal M

2+-M

3+

hydroxide layers with the interlayers occupied by charge-compensating anions and water molecules. In the hydroxide layers, the metal cations are coordinated by 6 hydroxyl ions in such a way that O-H bonds are perpendicular to the plane of the layers. LDHs are natural examples of immensely flexible chemical structure, in which the cations ratio M

2+/M

3+ can vary, thereby providing a possibility to alter

their magnetic properties in the case when at least one of M2+

and M

3+ is magnetic ion.

Here we report on the low-temperature glassy magnetic behaviour of Co

2+(n)Al

3+ LDHs with the fixed cobalt-to-

aluminum cations ratio (n = 2 and 3) and intercalated with NO3

- anion. Static magnetization was measured in zero-field-

cooled (ZFC) and field-cooled (FC) modes in low magnetic field of 100 Oe. Dynamic susceptibility was taken at different frequencies (up to 1 kHz).

It was found that ZFC and FC static magnetizations are strongly divergent. The distinct maximum in the ZFC magnetization, which coincides with the maximum in the

real part of the ac susceptibility (T) taken at the lowest frequency, was defined as the magnetic glass transition

temperature, Tg 4.5 K for Co(2)Al-NO3 and Tg 3.6 K for

Co(3)Al-NO3. Strongly divergent ZFC and FC static magnetizations together with frequency dependent ac susceptibility are evident of the glassy-like magnetic state.

The dynamic susceptibility appeared to be strongly frequency-dependent (Fig. 1). The frequency dependent

shifts of the cusp temperature Tf of the (T) curves, obtained as (ΔTf /Tf) per decade of frequency [1], were found as 0.015 and 0.048 for Co(2)Al-NO3 and Co(3)Al-NO3, respectively, indicate that the magnetic state of these compounds at low temperatures is rather close to canonical spin-glasses than to the superparamagnetics. At the same time, it was found that the frequency dependence of Tf in the ac susceptibility follows the empirical Vogel-Fulcher law [2]

ν = ν0 exp[-Ea/kB(Tf - T0)] with activation energy Ea/kB = 14.7 K and 12.8 K, and temperature T0 = 3.92 and 2.83 K, for Co(2)Al-NO3 and Co(3)Al-NO3, respectively. The obtained parameters indicate an interaction between the spins and the formation of a cluster glass state in the both studied LDHs.

Fig. 1. The temperature dependence of the real part of the ac susceptibility

(T) of Co2+(n)Al3+ LDHs with the fixed cobalt-to-aluminum cations ratio n = 2 (left panel) and n = 3 (right panel) and intercalated with NO3

-.

This work was supported by the EU H2020 project European Microkelvin Platform (EMP), grant agreement No. 824109. The authors acknowledge also the financial support through the Slovakia-Portugal bilateral project FAST-LDH (2019-2020)/APVV-SK-PT-18-0019 and the Belarus-Ukraine grant "Effect of magnetic field and ultrasound on the anion-exchange properties of iron- and cobalt-containing layered double hydroxides" (2020-2021) N0120U000216, Т20УКА-020.

REFERENCES

[1] J.A. Mydosh, Spin Glasses: An Experimental Introduction. Taylor & Francis, 1993.

[2] V.K. Anand, D.T. Adroja, A.D. Hillier, “Ferromagnetic cluster spin-glass behavior in PrRhSn3,” Phys. Rev. B, vol. 85, ID 014418, 2012.




03NMM07-1

The Internal Stresses Influence on the

Magnetostatic, Magnetostrictive and Dynamic

Properties of Fe-based Amorphous MicrowiresA. Litvinova

Institute of Physics & Technology and STP “Fabrika”,


Kaliningrad, Russia [email protected]

V. Rodionova

Institute of Physics & Technology and STP “Fabrika”,



Magneto-bistable microwires with a positive magnetostriction constant are perspective for their using as coding and logical devices due to the reached velocities of the domain walls motion [1, 2]. The search for ways to control the dynamics of the domain wall motion (velocity and mobility), the magnetization reversal process in such microwires have a wide range of tasks to apply amorphous ferromagnetic microwires in a range of technical applications, such as highly sensitive sensors of magnetic fields, stresses, low pressure, deformations and other physical parameters [3-5].

During the manufacturing process in amorphous ferromagnetic microwires coated with a glass shell the internal mechanical stresses arise due to the difference in the coefficients of metal and glass thermal expansion. These tensions affect the magnetostatic and magnetostrictive amorphous microwires properties. On the other hand the magnetostriction coefficient magnitude affects the dynamics of the domain wall motion in magneto-bistable microwires.

Investigation was carried out for amorphous ferromagnetic microwires in a glass shell, manufactured by the Ulitovsky-Taylor method, alloy Fe77.5Si17.5B15 with the ratio of the metal core diameter to the total diameter ρ=d/D= 12/27=0.44. As a result of the experiment hysteresis loops, domain wall velocities, magnetostriction coefficient were obtained. Also this magnetic characteristics were measured for the same samples after removing the glass shell. Removing the glass is done mechanically. The above magnetic parameters were determined by a device with an induction module.

Consider the obtained magnetic characteristics for one of the microwires and their changes owing to removing the glass shell. Initially for all samples the shape of the hysteresis loop was observed to be rectangular, that is the investigated microwires are magneto-bistable. After removing the glass shell, the samples show an s-shaped hysteresis loop.

Table 1 shows the results of the magnetic characteristics for one of the samples: coercive force HC (Oe), squareness coefficient k of the hysteresis loop, velocity V (km/s) at an external field H = 2.16 Oe, magnetostriction coefficient λS.

Removing the glass shell reduces the contribution of stresses that have arisen inside the metal core due to the difference in the coefficients of metal and glass thermal expansion, and, as a consequence, increases the contribution of quenching stresses.

TABLE I. THE MAGNETIC CHARACTERISTICS OF A SAMPLE FROM A

SERIES OF MICROWIRES WITH Ρ= 0.44.

Microwire HC, Oe k V, km/s λS*10-6

with glass 5.33 1 0.68 3.66

no glass 1.32 0.74 2.96 11.3

From table 1 a decrease in the value of the coercive force as well as the squareness coefficient can be seen after the removal of the glass shell for the investigated samples. An increase in the magnetostriction coefficient is observed. Such dependence is the result of a decrease in the internal stress caused by the shell presence. An increase in the mobility of the domain wall is obtained. Since the ratio of diameters d/D becomes equal to unity, i.e. it reaches the maximum value, respectively, the value of internal stresses is minimum.

REFERENCES

[1] A. Zhukov, “Glass-coated Magnetic Microwires for Technical Applications,” J. Magn. Magn. Mater., vol. 242-245, pp. 216-223, 2002.

[2] V. Rodionova, M. Ilyn, M. Ipatov, V. Zhukova, N. Perov, A. Zhukov, “Spectral Properties of Electromotive Force Induced by Periodic Magnetization Reversal of Arrays of Coupled Magnetic Glasscovered Microwires,” J. Appl. Phys., vol. 111, ID 07E735, 2012.

[3] P. Corte-León, V. Zhukova, M. Ipatov, J.M. Blanco, J. Gonzalez, L. Dominguez, M. Churyukanova, A. Zhukov, “High Frequency Giant Magnetoimpedance Effect of a Stress-annealed Fe-rich Glass-coated Microwire,” J. Alloy. Compd., vol. 802, pp. 112-117, 2019.

[4] M.-H. Phan, H.-X. Peng, “Giant Magnetoimpedance Materials: Fundamentals and Applications,” Prog. Mater. Sci., vol. 53, no 2, pp. 323-420, 2008.

[5] A. Zhukov, V. Zhukova, Magnetic Properties and Applications of Ferromagnetic Microwires with Amorphous and Nanocrystalline Structure, NY: Nova Science Publishers, Inc., 2009.




03NMM08-1

Exchange Inertia Effects in Artificial Neural

Networks Using Antiferromagnetic Oscillators

Hannah Bradley


Oakland University

Rochester, MI, USA [email protected]

Vasyl Tyberkevych


Oakland University


Antiferromagnetic (AFM) spin Hall oscillators driven by an external sub-threshold current can create ultra-short spikes in response to a weak external stimulus and therefore can be used as ultra-fast artificial neurons [1, 2]. The duration of the output neuron spike is determined, mainly, by the anisotropy of the AFM material and typically is of the order of a few ps, while the strength of the external bias current determines the minimum possible delay between two consecutive spikes (“refractory time” of an AFM neuron), which can be as low as ~ 100 ps. One of specific features of AFM oscillators is an effective inertia that originates from exchange coupling between two magnetic sublattices [3].

Here we investigate dynamical behavior of such inertial AFM-based neural networks not possible with conventual artificial neurons. The simplest manifestation of the exchange inertia is the delay of the spike generated by an AFM neuron relative to the input stimulus signal. This effect can be used to create a periodic spike generator by coupling several AFM neurons in a ring structure. The spiking period of such generator can be continuously tuned by changing the coupling between the neurons. These rings are able to hold more than one signal in the loop the length of delay between neurons, which can be as low as ~100 ps. The exchange inertial effects can also be used to create a circuit in which propagation of a spike is suppressed in the presence of another signal. Combining the inhibitor circuit with a ring structure allows one to create a controllable neuromorphic memory loop (see example simulations in Fig. 1), which is “switched on” by applying an input spike to one of the neurons in the ring structure and can be “switched off” using the inhibiting signal.

Fig. 1. Example simulations of a controllable memory loop based on artificial AFM neurons. Top panel: time profiles of input spikes featuring two “start” signals (at 100 ps and 800 ps) and one “inhibitory/stop” signal (at 500 ps). Bottom panel: output spike sequence generated by the memory loop.

REFERENCES

[1] R. Khymyn, I. Lisenkov, J. Voorheis, O. Sulymenko, O. Prokopenko, V. Tyberkevych, et al., “Ultra-fast Artificial Neuron: Generation of Picosecond-duration Spikes in a Current-driven Antiferromagnetic auto-oscillator,” Sci. Rep., vol. 8, ID 15727, 2018.

[2] O. Sulymenko, O. Prokopenko, I. Lisenkov, J. Åkerman, V. Tyberkevych, A. Slavin, et al., “Ultra-fast Logic Devices Using Artificial “Neurons” Based on Antiferromagnetic Pulse Generators,” J. Appl. Phys., vol. 124, ID 152115, 2018.

[3] R. Khymyn, I. Lisenkov, V. Tiberkevich, B. Ivanov, A. Slavin, “Antiferromagnetic THz-frequency Josephson-like Oscillator Driven by Spin Current,” Sci. Rep., vol. 7, ID 43705, 2017.




03NMM09-1

Unitary Magnon-mediated Quantum Computing

Operations

Cody Trevillian


Oakland University


Vasyl Tyberkevych


Oakland University


A basis of a promising hybrid quantum computing architecture is formed by coupled magnonic and photonic resonators with strong coupling rates (> 100 MHz) [1-6]. Magnetic field tunability of magnon resonant frequencies allows one to reconfigure such systems during a quantum computation. Here, we show that, at timescales comparable to the magnon-photon energy exchange time, dynamic tuning of magnon frequencies allows one to achieve qualitatively new functionalities of such hybrid devices.

One example of qualitatively new functionality can be realized using a linear ramp of magnon resonant frequency to controllably couple and uncouple a magnonic resonator to multiple photonic resonators that are not coupled to one another. When such linear ramping is performed, information initially contained in one photonic resonator can be coherently transferred to another using the magnonic resonator as an intermediary. Fig. 1 shows simulation of this coherent information transfer between two mutually uncoupled & nondegenerate photonic resonators P1,2 that are dynamically coupled in-time to a magnonic resonator Pm. Such linear ramping of magnon frequency is performed in the adiabatic regime and is realized via a prescribed pulsed magnetic field profile.

By shaping the profile of the pulsed magnetic field that controls magnon frequency, different gates can be realized in the same physical structure. In particular, we demonstrate theoretically the possibility of realization of several unitary magnon-mediated quantum gates, such as entanglement generation and coherent quantum data exchange. It should be noted, that decoherence processes in magnonic resonators have a very weak effect on the overall performance of the proposed gates and our estimates show that magnon-mediated operations may have efficiencies better than existing quantum gate designs.

Fig. 1. Temporal population profiles of magnon-mediated coherent

information transfer between two photonic resonators P1,2 (top panel)

coupled to magnonic resonator Pm (bottom panel) using linearly ramped pulsed magnetic field profile.

REFERENCES

[1] H. Huebl, C. W. Zollitsch, J. Lotze, F. Hocke, M. Greifenstein, A. Marx, et al., “High Cooperativity in Coupled Microwave Resonator Ferrimagnetic Insulator Hybrids,” Phys. Rev. Lett., vol. 111, ID 127003, 2013.

[2] Y. Tabuchi, S. lshino, T. Ishikawa, R. Yamazaki, K. Usami, Y. Nakamura, “Hybridizing Ferromagnetic Magnons and Microwave Photons in the Quantum Limit,” Phys. Rev. Lett, vol. 113, ID 083603, 2014.

[3] X. Zhang, C.-L. Zou, L. Jiang, H. X. Tang, “Strongly Coupled Magnons and Cavity Microwave Photons,” Phys. Rev. Lett., vol. 113, ID 156401, 2014.

[4] Y. Tabuchi, S. lshino, A. Noguchi, T. Ishikawa, R. Yamazaki, K. Usami, et al., “Coherent Coupling Between a Ferromagnetic Magnon and a Superconducting Qubit,” Science, vol. 349, no 6246, pp. 405-408, 2015.

[5] Y. Li, T. Polakovic, Y.-L. Wang, J. Xu, S. Lendinez, Z. Zhang, et al., “Strong Coupling Between Magnons and Microwave Photons in On-chip Ferromagnet-superconductor Thin-film Devices,” Phys. Rev. Lett., vol. 123, ID 107701, 2019.

[6] J. Hou, L. Liu, “Strong Coupling Between Microwave Photons and Nanomagnet Magnons,” Phys. Rev. Lett., vol. 123, ID 107702, 2019.




03NMM10-1

Thermal Noise Effects on Sweep-tuned Spectrum

Analyzer Accuracy

Peter Elphick


Oakland University


Vasyl Tyberkevych


Oakland University

Rochester, MI, USA

[email protected]

Steven Louis

Department of Electrical and Computer

Engineering

Oakland University


Andrei Slavin


Oakland University


Petro Artemchuk


Oakland University


Rapid sweep-tuning of nano-sized spin-torque nano-oscillators (STNO) though variation of the bias direct current show promise for use in ultra-fast (tuning speed ~100 MHz/ns) sweep-tuned spectrum analyzers [1,2]. In such devices, frequency determination is functionally limited by contrasting behaviors that occur at opposing ends of the operational range of tuning speeds. At one end of the operational range of tuning speeds, the bandwidth theorem determines the resolution of frequency determination when tuning speeds of the STNO are relatively high. On the other end of the operational range of tuning speeds, when tuning speeds are relatively low, thermal noise determines the generation linewidth of the STNO, which dictates the limiting factor in the accuracy of frequency determination.

Here, we investigate the impact of thermal noise on the limiting factors of the accuracy and resolution of frequency determination in rapidly sweep-tuned STNO spectrum analyzers. Our numerical simulations of the operation of such spectrum analyzers show an interesting measurement of a “jitter” behavior, which arises as a random shift of the spectral peak that governs the measurement of an external signal’s frequency. Numerical simulations performed with two-tone input signals reveal a high degree of correlation of

jitter-induced shifts for two spectral signals with close frequencies. This means, that the jitter noise limits the accuracy of absolute frequency measurements with an STNO-based spectrum analyzer, but has almost no influence on relative frequency measurements and resolution bandwidth of the analyzer. Moreover, the output jitter noise is practically independent of the scanning rate and its influence becomes negligible for scanning rates exceeding the STNO generation linewidth. Thus, our results prove that the thermal noise does not diminish operational characteristics of STNO-based spectrum analyzers in the regime of ultra-fast scanning, in which application of STNO is most interesting from the practical point of view.

REFERENCES

[1] S. Louis, O. Sulymenko, V. Tiberkevich, J. Li, D. Aloi, O. Prokopenko, et al., “Ultra-fast Wide Band Spectrum Analyzer Based on a Rapidly Tuned Spin-torque Nano-oscillator,” Appl. Phys. Lett., vol. 113, ID 112401, 2018.

[2] A. Litvinenko, V. Iurchuk, P. Sethi, S. Louis, V. Tyberkevych, J. Li, et al., “Ultrafast Sweep-tuned Spectrum Analyzer with Temporal Resolution Based on a Spin-torque Nano-oscillator,” Nano Lett., vol. 20(8), pp. 6104-6111, 2020.




03NMM11-1

Longitudinal Relaxation of Domain Walls in

Ultrathin Ferromagnets Ivan A. Yastremsky

Taras Shevchenko National University

of Kyiv


Nikolai. E. Kulagin

Frumkin Institute of Physical Chemistry

and Electrochemistry

Moscow, Russia

Jürgen Fassbender

Helmholtz-Zentrum Dresden -

Rossendorf e.V. Dresden, Germany

Boris A. Ivanov


of Kyiv

Kyiv, Ukraine

Denys Makarov

Helmholtz-Zentrum Dresden -

Rossendorf e.V.

Dresden, Germany [email protected]

Since the formulation of the phenomenological theory of the magnetization dynamics in 1935 [1], the transversal picture of the magnetization relaxation was totally dominating [2], when describing linear magnetic excitations (spin waves) and motion of nonlinear magnetic excitations including domain walls (DWs), bubbles, droplets and recently skyrmions.

In ultrathin magnetic films with thicknesses of the order of 1 nm, the damping constant is substantially enhanced (also refereed to as the enhanced Gilbert damping) and is dominated by the spin pumping mechanism [3]. The enhanced Gilbert damping parameter is determined based on the ferromagnetic resonance (FMR) measurements resulting in the damping constant of (0.04-0.22) for thin Co films [3,4]. This value is considerably larger than for bulk Co (0.005-0.01) [3]. When the damping constant is extracted from the DW mobility experiments, its value for ultrathin Co-based films is found to be larger than the damping constant determined from FMR. Thus, the enhancement of the damping for the case of DWs moving in ultrathin ferromagents cannot be explained in the framework of the transversal relaxation mechanism.

We consider an ultrathin ferromagnetic film with the out-

of-plane easy axis of magnetization M and interface-induced Dzyaloshinskii-Moria interaction (DMI) stemming from an asymmetry at the interfaces. The film accommodates a DW and its position can be manipulated with an external out-of-plane magnetic field. In the temperature range up to room temperature, typical asymmetric sandwiches containing ultrathin ferromagnetic films can be considered as two-

dimensional [4]. We describe the dynamics of M in the frame of the Landau--Lifshitz--Bar`yakhtar equation (LLBar) [2], which allows for description of both transversal and longitudinal (the change of the length of the

magnetization M M ) dynamics. Without loss of

generality, we assume that the DW moves along x axis.

Using the LLBar equation and assuming the relativistic relaxation tensor to be anisotropic with respect to the magnetization, the rate of the energy dissipation per unit area of the DW can be calculated.

We investigate the structure of M in moving DWs. Fig. 1 demonstrates that M is suppressed at the center of the DW. With the increase of the velocity, the depth of the dip in M decreases and this dip is shifted oppositely to the direction of motion.

Fig. 1. The dependence of the longitudinal change of the magnetization

0M M on x vt and different velocities of the moving DW. Here is

the longitudinal magnetic susceptibility at thermodynamic equilibrium at

zero magnetic field, KH is the anisotropy field, is the DW thikness, v is

the velocity of the DW and 0M is the equilibrium value of M at given

temperature.

We calculate the influence of the longitudinal dynamics on the energy dissipation (longitudinal relaxation) of moving DWs. We demonstrate that when describing the motion of DWs in typical ultrathin ferromagnetic films with perpendicular anisotropy and DMI, the influence of the longitudinal relaxation on the dynamics of magnetic DWs is comparable or stronger than the transversal relaxation. The impact of the longitudinal relaxation mechanism for bulk transition metals Co, Ni or Permalloy is negligible. The presence of DMI can suppress or enhance the longitudinal relaxation. The contribution of the longitudinal relaxation deacreases as the velocity increases.

REFERENCES

[1] L.D. Landau, E.M. Lifshits, “On the Theory of the Dispersion of Magnetic Permeability in Ferromagnetic Bodies,” Perspectives in Theoretical Physics, The Collected Papers of E.M. Lifshitz, pp. 51-65, 1992.

[2] V.G. Bar'yakhtar, “Phenomenological Description of Relaxation Processes in Magnetic Materials,” Zh. Eksp. Theor. Fiz., vol. 87, pp. 1501, 1984. [Sov. Phys. JETP, vol. 60, pp. 863, 1984].

[3] Y. Tserkovnyak, A. Brataas, G.E. W.Bauer, “Enhanced Gilbert Damping in Thin Ferromagnetic Films,” Phys. Rev. Lett., vol. 88, ID 117601, 2002.

[4] I.A. Yastremsky, et al., “Thermodynamics and Exchange Stiffness of Asymmetrically Sandwiched Ultrathin Ferromagnetic Films with Perpendicular Anisotropy,” Phys. Rev. Appl., vol. 12, ID 064038, 2019.




03NMM12-1

Circular Stripe Domains Imprinted

into the Out-of-Plane Magnetised Material

Oleksandr Zaiets

Faculty of Radiophysics, Electronics and Computer Systems

Taras Shevchenko National University of Kyiv

Kyiv, Ukraine

[email protected]

Denis Makarov

Helmholtz-Zentrum Dresden-Rossendorf e.V.

Institute of Ion Beam Physics and Materials Research

Dresden, Germany

[email protected]

Denis Sheka

Faculty of Radiophysics, Electronics and Computer Systems

Taras Shevchenko National University of Kyiv


Volodymyr Kravchuk

Institut für Theoretische Festkörperphysik

Karlsruher Institut für Technologie

Karlsruhe, Germany [email protected]

Engineered magnetic textures are prominent for numerous sensors, data storage and processing applications. Magnetic films with perpendicular anisotropy are well-known to exhibit transverse instability resulting in nucleation of stripe domains [1]. The key role in the stripe domain formation plays the nonlocal magnetostatics interaction. Typically, such instability is realized by applying an in-plain magnetic field. An alternative way to create magnetic texture can be realized by stacking two magnetic layers with in-plane and out-of-plane magnetization, providing an efficient way to create a variety of magnetic states even with different topological properties [2].

Fig. 1. Magnetization structure of circular stripe domains induced by

interlayer exchange coupling between the Cobalt nanodisk and Permalloy

nanodisk (interlayer exchange (RKKY) coupling constant σ = 0.38 mJ/m2).

The following parameters of the Co disk were used in OOMMF simulations: disk radius R=500nm, thickness L = 8 nm, exchange constant

A = 2·10-11 J/m, saturation magnetization Ms = 5·105 A/m, easy-normal

anisotropy K = 2·105 J/m3. Arrows show the in-plane magnetization distribution and colours correspond to the mz component.

Here we consider a vertically stacked magnetic heterostructures Py/Pd/Co of cylindrical geometry. Due to the interlayer exchange coupling between the thick vortex-state Py nanodisk and thin Co layer a vortex structure is induced in the Co nanodisk. A new circular stripe domain state over the vortex background is realized due to the competition between local and nonlocal interactions. Consecutive phase transitions between the vortex state, the circular stipe domain and the vortex cone phase take place by tuning the interlayer exchange coupling parameter and Co disk thickness. Circular stipe domains magnetic structure on the top of Co disk is represented in Fig.1. The detailed analysis of remanent states is performed by means of micromagnetic simulations. The existence of circular stripe domains corresponds to experimentally detected donut state [2].

REFERENCES

[1] A. Hubert, R. Schäfer, Magnetic Domains: the Analysis of Magnetic Microstructures, Springer, 2009.

[2] R. Streubel, et al., “Co-overexpression of Geraniol-10-hydroxylase and Strictosidine Synthase Improves Anti-cancer Drug Camptothecin Accumulation in Ophiorrhiza Pumila,” Sci. Rep., vol. 5, ID 8227, 2015.




03NMM13-1

Surface Magnon-Plasmon-Polariton Resonance in a

Shielded Ferromagnetic Film

Oleksii Malyshev

Faculty of Radio Physics, Electronics

and Computer Systems


of Kyiv

Kyiv, Ukraine

[email protected]

Volodymyr Malyshev




of Kyiv

Kyiv, Ukraine

[email protected]

Oleksandr Prokopenko




of Kyiv

Kyiv, Ukraine

[email protected]

Magnetoplasmonics is an emergent field of modern magnetism [1]. Multilayer magnetoplasmonic systems utilizing magnons, plasmons and polaritons are now considering as promising base elements of microwave and terahertz-frequency electronics of the future [1, 2]. Typically such systems consist of two or more thin layers made of different materials (for instance, one metal and one magnetic layers) [2]. However, in this paper we experimentally demonstrate for the first time that a thin film made of a ferromagnetic metal can manifest itself as a magnetoplasmonic device possessing a surface magnon-plasmon-polariton (SMPP) resonance.

We experimentally investigate SMPP resonance in a ferromagnetic permalloy (Py) film by measuring the bias magnetic field dependence of the frequency shift caused by the SMPP resonance (Fig. 1). The film is a natural resonance surface plasmon-polariton system, so-called the surface electromagnetic wave resonator (SEWR) [3]. In the absence of bias magnetic field the frequency of this resonance mainly depends on the lateral sizes l, w of the film [3]. However, in the presence of bias magnetic field magnons in Py film are excited, and a complex SMPP resonance can be formed, if the magnon frequency coincides with the frequency of surface plasmon-polariton oscillations [4].

The research was carried out in X-band using scalar network analyzer R2-61 and the method of microwave reflectometry [3]. SEWR in a form of Py film was situated inside a standard X-band rectangular waveguide and the distance d between the film and the waveguide wall could be changed during the experiment. Such a system can be considered as a shielded ferromagnetic film, where the nearest waveguide wall works as a conducting metal shield. An analytical theory of SMPP in such a shielded ferromagnetic film has been developed in [4] recently.

SEWR spectrum of oscillations consists of longitudinal modes (resonance size w along the waveguide axis) and transversal modes (resonance size l perpendicular to the waveguide axis) [3]. The first group of modes is inconvenient for magnetoplasmonic applications, therefore to eliminate it, the resonator was situated in a rotated by 90 degree X-band rectangular waveguide forming a below cutoff waveguide. In order to obtain a high Q-factor of the SEWR, it is situated at the center of the waveguide far from the walls, but parallel to a wide wall of the input, non-rotated waveguide, at some optimum distance z from the junction between the rotated and non-rotated X-band rectangular waveguides.

The Fig. 1 shows the experimental dependences for a SEWR made of Py film having lateral sizes 11,3 mm × 1,3 mm and thickness 0,4 mm. The presented curves demonstrate that the frequency shift of the SEWR’s fundamental oscillation due to the existence of the SMPPs can reach ~1%, which is in a good agreement with theoretical prediction [4]. Also the observed effect intensifies with the decrease of distance d between the SEWR and the nearest waveguide wall.

Fig. 1. Experimental dependences of the normalized surface plasmon-

polariton resonant frequency on the bias magnetic field BDC applied

parallel to the Py film. The film is a SEWR situated inside a bellow cutoff rotated rectangular waveguide and d is the distance between the

film and the metal screen (wide wall of the waveguide).

We believe that the obtained results can be useful for the development of novel magnetoplasmonic devices operating in a microwave range. The publication contains the results of studies conducted by the grants 19BF052-01 and 18BF052-01M from Taras Shevchenko National University of Kyiv.

REFERENCES

[1] Surface Electromagnetics: With Applications in Antenna, Microwave, and Optical Engineering. Edited by F. Yang, Y. Rahmat-Samii, Cambridge Univ. Press, 2019.

[2] D. Mart´ın Becerra, Active Plasmonic Devices Based on Magnetoplasmonic Nanostructures, Springer, 2017.

[3] G.A. Melkov, Y.V. Egorov, O.M. Ivanyuta, V.Y. Malyshev, H.K. Zeng, Kh. Wu, J.Y. Juang, “HTS Surface Wave Resonators,” J. Supercond., vol. 13, pp. 95-100, 2000.

[4] V.Yu. Malyshev, I.V. Zavislyak, G.A. Melkov, M.O. Popov, O.V. Prokopenko, “Microwave Magnon-plasmon-polaritons in the Ferromagnetic Metal–screened Insulator Structure,” Ukr. J. Phys., vol. 65, no. 10, pp. 939-948, 2020.




03NMM14-1

Magnonic Crystal Based on YIG/Hexaferite Films

Vladyslav Kariachka




of Kyiv


Vladyslav Romaniuk




of Kyiv

Kyiv, Ukraine

[email protected]

Volodymyr Malyshev




of Kyiv


Viсtor Kostenko

Institute of High Technologies


of Kyiv

Kyiv, Ukraine

[email protected]

Oleksandr Prokopenko




of Kyiv

Kyiv, Ukraine

[email protected]

Dmytro Bozhko


University of Colorado at Colorado

Springs

Colorado Springs, USA [email protected]

Magnonic cystals (MCs) are subjects of great interest in modern microwave magnetism due to its unique physical properties and a large number of possible practical applications of such systems [1]. In MCs, there is a periodic change of the magnetization vector, which leads to the formation of band gaps for spin waves, and appearance of others effects similar to the effects in real crystals [1].

In this paper we report the creation of reconfigurable MC based on a bilayer magnetic system, where one layer is a thin yttrium-iron garnet (YIG) film and the other layer is a well-polished barium hexaferite (BHF) plate (Fig. 1). Due to a strong interaction between magnetic subsystems of YIG and BHF, BHF plate impose its domain structure (DS) on the YIG film, which, in turn, leads to the formation of MC in the YIG film.

Fig. 1. Model of the investigated MC: YIG film (top layer) placed on the

BHF film (bottom layer). Arrows show the directions of magnetization vectors in magnetic domains, black lines indicate the domain walls.

Using a polarizing microscope, we observe the DS in YIG layer (Fig. 2) and detect reconfiguration of the DS in the YIG under the action of bias magnetic field (Fig. 3). For greater clarity, we investigate a section of the formed MC located near the edge of BHF layer (YIG film lateral boundaries do not coincide with the lateral boundaries of BHF plate, see Fig. 1). As one can see from Fig. 2 in a section of the YIG film, located just on top of the BHF plate, the typical DS of the YIG changes to a cylindrical DS, which is specific for BHF layer. However, this formed cylindrical DS is not ideal, which can be explained by the nonzero thickness and impurities of the contact area between the magnetic layers.

Fig. 2. Photograph of the DS at the boundary of the hexaferrite layer.

Fig. 3 demonstrates that by applying a sufficient perpendicular bias magnetic field, the periodicity of the MC can be changed. While at zero field an average size of a cylindrical domain is about 20 μm, this size can be reduced down to 5 μm at the field ~ 800 Oe.

Fig. 3. DS of investigated MC observed at different values of the applied

bias magnetic field: (a) 0 Oe; average size of a cylindrical domain is

20 μm, (b) 388 Oe; the size is 10 μm, (c) 801 Oe; the size is 5 μm.

In conclusion, we have created a YIG-BHF based MC, which can be reconfigured by a perpendicular bias magnetic field. We believe that such crystals can be promising for some magnonic devices operating at microwaves. The publication contains the results of studies conducted by the grants 19BF052-01 and 18BF052-01M from Taras Shevchenko National University of Kyiv.

REFERENCES

[1] A.A. Serga, A.V. Chumak, B. Hillebrands, “YIG magnonics,” J. Phys. D: Appl. Phys., vol. 43, no. 26, ID 264002, 2010

(а) (b)

(c)




03NS01-1

Photovoltaic, Photocatalytic and Microfluidic

Energy Harvesters for Autonomous Sensor Systems

Ivan Turkevych National Institute of Advanced Industrial Science and Technology, Sensing System Research Center

Tsukuba, Japan

[email protected]

Autonomous nanosensors are expected to improve living standards by monitoring parameters of environment, such as temperature, humidity, illumination, air quality, water contamination, objects proximity, integrity of infrastructure, etc. Environmental nanosensors are viewed as an important part of the future internet-of-things IoT ecosystem providing diverse sensing data that can be used for effective decision making, adaptive control and energy saving.

Fig. 1. Power consumption of electronic devices and range of photovoltaic

power generation under indoor artificial and outdoor solar light, in W/cm2

Currently IoT devices are either grid connected or rely on alkaline batteries as power sources, which have limited lifetime. Harvest of ambient energy, such as indoor and outdoor light, represents a viable solution for development of autonomous, “install-and-forget”, IoT sensors, which do not require periodic battery replacement with associated labor costs usually exceeding the cost of the sensors. In my presentation I will compare different PV technologies and demonstrate that thin-film hybrid perovskite photovoltaic cells demonstrate superior performance under both outdoor solar and indoor artificial illumination.

Fig. 2. (a) Schematic illustration of polyiodide assisted method for

conversion of (b) nanoscale Pb layers to (c) hybrid MAPbI3 perovskite

films and (d) J-V characteristics, (e) external quantum efficiency and (f)

cross-section structure of perovskite photovoltaic cell [1]

In addition to outstanding performance, perovskite PV cells bring other advantages, such as low-temperature processability, scalability and flexibility that allow their effective integration into sensing devices. I will highlight our recent discovery of polyiodide-assisted conversion of nanoscale metallic Pb layers to hybrid perovskite thin films [1] and explain advantages of this technology for development of integrated PV devices.

Fig. 3. (a) Schematic illustration of micro-power photocatalytic-fuel cell

on a microfluidic platform, (b) photocatalytic core-shell WO3/BiVO4

nanorods, (c) photocurrent and power generation under solar illumination and (d) extended nanofluidic channels [2]

The intermittent nature of solar light, as well as indoor light, implies the necessity of integrated energy storage devices. Combination of a PV cell with an electrochemical battery is a widely applied and trivial solution that is not optimal in many cases, considering system complexity, energy efficiency and power to size and weight ratios. Power sources combining PV cells with energy-storing supercapacitors are being developed for nanosensors. In addition, I will demonstrate an alternative concept of micropower energy harvester, where a photocatalytic hydrogen generator is integrated with a micro fuel cell in a single microfluidic platform [2, 3].

REFERENCES

[1] I. Turkevych et al., “Strategic advantages of reactive polyiodide melts for scalable perovskite photovoltaics,” Nat. Nanotech., vol. 14, pp. 57–63, 2019.

[2] Y. Pihosh et al, “From Extended Nanofluidics to an Autonomous Solar-Light-Driven Micro-Fuel-Cell Device,” Angew. Chem., vol. 129, pp. 8242-8245, 2017.

[3] Y. Pihosh et al., “Ferroelectric Extended Nanofluidic Channels for Room‐Temperature Microfuel Cells,” Adv. Mater. Technol., vol. 4, ID 1900252, 2019.




03NS02-1

Zinc Oxide Doped Tungsten Trioxide Nanostructure

for Ethanol Gas Sensor Applications

G. Adilakshmi, A. Sivasankar Reddy

Department of Physics, Vikrama Simhapuri University P.G. Centre Pradesh, India [email protected]

P. Sreedhara Reddy

Department of Physics, Sri Venkateswara University, Tirupati, India

In this paper, we report zinc oxide (ZnO) doped tungsten trioxide (WO3) nanostructures were successfully deposited on a glass substrate via an electron beam evaporation technique. The microstructure, surface morphology, chemical composition,

crystal structure, and optical properties of the pure and ZnO

doped WO3 nanostructure thin films were studied by scanning

electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer and

photoluminescence spectroscopy (PL). Gas sensing tests

revealed that the ZnO doped WO3 nanostructure possesses excellent gas-sensing performance for ethanol. The best sensing performance was observed at an operating temperature between 250-300

oC. The ZnO doped films showed a fast

response, recovery time compares to undoped WO3 films. Ethanol sensors are especially useful and extensively used in many fields such as industry, medical, food processing, and cleaning.




03NEE01-1

1D Nanostructure Materials for the Energy

Conversion

Yuriy Pihosh, Kazunari Domen

University Professors Office, The University of Tokyo

Japan [email protected]

Vikas Nandal, Kazuhiko Seki

Nanomaterials Research Institute, National Institute of Advanced

Industrial Science and Technology Tsukuba, Ibaraki, Japan

Market commercialization of photocatalytic water splitting

requires a solar-to-hydrogen (STH) efficiency of at least 10%,

which depends on properties such as solar light absorption,

efficient generation, separation, and transport of free charge

carriers to the surface for the hydrogen evolution reaction.

Therefore, it is imperative to optimise the material properties

and device structure to achieve the above-mentioned

prerequisites, to develop high performance photocatalytic

devices. A nanostructured film of well vertically aligned and

separated rod is considered as an ideal light harvesting device

structure, where, the photogenerated holes and electrons inside

the nanorods (NRs) can easily diffuse along the NRs radius

toward the side surface and along the NRs length to reach the

conductive substrate, respectively. Such selective or

asymmetric charge transport has potential of reducing the

recombination loss and thereby enhances performance

metrices. As a result, the photocurrent in the NRs-based

photoanode can be maximised by separate optimization of the

optical and electronic thicknesses, namely, sufficiently longer

NRs with an optimal diameter will allow light trapping to fully

absorb incident solar light, and a small radius of the NRs

comparable to the diffusion length will effectively separate the

photogenerated charge carriers. Thus, we expect not only

superior photoelectrochemical (PEC) properties of NRs-based

photoanodes but also suppression of the onset potential.

Among different known techniques for the fabrication of

1D nanostructured materials, the Glancing Angle Deposition

(GLAD) is one of the famous techniques which allows the

fabrication of nanostructured film composed of NRs with high-

aspect ratio. Additionally, the GLAD system, equipped with

the sputtering source (ex. R.f magnetron), facilitate the

realization of nano structuring of various kinds of oxy/nitride

materials. As an example, in our previous works, we

demonstrated the possibility of preparing 1D nanostructure

heterojunction photoanodes based on vertically aligned WO3-

NRs/BiVO4 [1] and Ta3N5-NRs/BaTaON [2]. In particular,

WO3-NRs/BiVO4 photoanode exhibits ultimate water splitting

photocurrent of 6.72 mA cm−2

under 1 sun illumination at

1.23V (versus RHE) that corresponds to ~90% of the

theoretically possible value for BiVO4. The fabricated

photoanode in tandem with a double-junction of

GaAs/InGaAsP photovoltaic cell demonstrated the STH of

8.1%. Unfortunately, for BiVO4, the band gap of 2.4 eV limits

the theoretical STH conversion efficiency to 9.2%. Therefore,

other photocatalytic material with relatively narrow bandgap of

~1.9-2.1eV is required for STH > 10%. Tantalum nitride

(Ta3N5), with band gap 2.1 eV, is one of the most promising

contender for water splitting with a maximum possible STH

efficiency of ~15.7%. By optimizing the GLAD and nitridation

parameters, we fabricated highly efficient polycrystalline

Ta3N5-NRs/FeNiOx-based photoanode that consists of

aggregated single-crystalline large grain domains [3]. We

demonstrated that the large grain domains in a Ta3N5 nanorod

improve its conductivity and provide enhanced light harvesting

owing to efficient generation and extraction of charge carriers.

This leads to a saturated photocurrent of 9.95 mA cm−2

at 1.05

VRHE, fill factor ~ 42% which delivers a state-of-the-art solar

energy conversion efficiency of 2.72% for single-photon

photoanodes, Fig. 1. To the best of our knowledge, for the first

time, we realize a photocurrent density of ~10 mA cm−2

at 1.1

VRHE with good stability for the OER showing continuous

retention of 80% after 70 minutes. Our results represent a

significant step forward towards the realization of a solar to

hydrogen conversion efficiency of more than 10% for practical

solar hydrogen production.

Additionally, we demonstrated other practical

applications of 1D nanostructure for lithium ion batteries

(LIBs) [4]. The controlled geometry of the tungsten oxide

NRs minimized volumetric expansion effects, which

conferred high mechanical stability to the anode as well as

LIBs performance.

Fig. 1 Schematic illustration of the photocatalytic water splitting process on

Ta3N5-NRs (left side), and PEC performance of the fabricated photoanode

(right side)

REFERENCES [1] Y. Pihosh, et al., “Photocatalytic Generation of Hydrogen by Core-shell

WO3/BiVO4 Nanorods with Ultimate Water Splitting Efficiency,” Sci.

Rep., vol. 5, ID 11141, 2015.

[2] Y. Pihosh, et al., “Development of a Core–Shell Heterojunction Ta3N5-

Nanorods/BaTaO2N Photoanode for Solar Water Splitting,” ACS

Energy Lett., vol. 5, pp. 2492-2497, 2020.

[3] Y. Pihosh, et al., “Ta3N5-Nanorods Enabling Highly Efficient Water Oxidation via Advantageous Light Harvesting and Charge Collection,”

Energy Environ. Sci., vol. 13, pp. 1519-1530, 2020.

[4] R. Bekarevich, et al., “Conversion Reaction in the Binder-Free Anode for Fast-Charging Li-Ion Batteries Based on WO3 Nanorods,” ACS

Appl. Energy Mater., vol. 3, pp. 6700-6708, 2020.




03NEE02-1

Calcium Copper Titanate Based Nanocomposites

for the Photoelectrocatalytic Wastewater Treatment

Fida Tanos

Institut Européen des Membranes,IEM,

Univ Montpellier, CNRS, ENSCM

Laboratoire des Analyses Chimiques,

Faculté des Sciences 2, Université

Libanaise

Montpellier, France

Fanar, Liban

[email protected]

Geoffroy Lesage

Institut Européen des Membranes, IEM,


Montpellier, France

[email protected]

Antonio Razzouk

Laboratoire des Analyses Chimiques,

Faculté des Sciences 2, Université

Libanaise

Fanar, Liban [email protected]

Mikhael Bechelany

Institut Européen des Membranes, IEM,


Montpellier, France [email protected]

Marc Cretin

Institut Européen des Membranes, IEM, Univ Montpellier, CNRS, ENSCM

Montpellier, France

[email protected]

Contamination of water bodies by harmful and recalcitrant organic substances is a global challenge, which is difficult to treat with the conventional wastewater treatment processes. A promising environmentally friendly technique for a more efficient removal of these pollutants is the photoelectrocatalysis (PEC) which combines electrolytic and photocatalytic processes. PEC is a form of advanced oxidation technique which deals with in situ production of active oxidizing species such as hydroxyl radicals, superoxide radicals and holes which oxidizes organics to water and carbon dioxide [1]. Herein, we report the transformation of emerging pharmaceutical pollutants under visible irradiation via PEC process. Thus controlling the photoelectrode materials is an essential step in designing new materials for wastewater treatment. A cubic Calcium copper titanate (CaCu3Ti4O12 (CCTO)) based nanocomposite doped with 2D materials (Boron nitride or Graphene Oxide) has been synthesized. The crystallinity and morphology of the materials were characterized with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). In order to investigate the optical properties, UV-Vis diffuse reflectance and photoluminescence spectroscopies were used. The electrochemical activity was evaluated with cyclic and linear voltammetry measurements, and the resistivity of samples was assessed with impedance spectroscopy in dark and under visible light irradiation in alkaline solution. Finally, photoelectrochemical properties of the photoanode were investigated through the degradation of paracetamol in pure water. The degradation efficiency was monitored using high performance liquid chromatography (HPLC) and the mineralization processes were studied through TOC analysis. The acute toxicity (Microtox) of potential by-products following the degradation was also investigated

Fig. 1. Photoelectrochemical degradation of paracetamol

REFERENCES

[1] M.G. Peleyeju, E.H. Umukoro, L. Tshwenya, R. Moutloali,

J.O. Babalola, O.A. Arotiba, “Photoelectrocatalytic water treatment

systems: degradation, kinetics and intermediate products studies of sulfamethoxazole on a TiO2-exfoliated graphite electrode,” RSC

Adv., vol. 7, no 64, pp. 40571-40580, 2017.

Organic Pollutant

s

CO2+H2O

e-

e-

+

+

+

+

+

+

+

-

-

-

-

-

-

-




03NEE03-1

Magnetic Field Assisted-Nanocatalysis for

Industrial Wastewater Treatment

A. Gallo-Cordova, J.G. Ovejero,

M.P. Morales

Group of Materials for Medicine and

Biotechnology Instituto de Ciencia de

Materiales de Madrid ICMM/CSIC

Madrid, Spain

[email protected]

J.J. Castro, D. Almeida

Streitwieser Institute for the

Development of Alternative Materials

and Energies Universidad San

Francisco de Quito USFQ

Quito, Ecuador

[email protected]

E.L. Winkler, E. Lima Jr., R.D. Zysler

Centro Atómico de Bariloche Instituto

de Nanociencia y Nanotecnología,

CNEA, CONICET

Bariloche, Argentina [email protected]

Engineered inorganic nanoparticles like iron oxide nanoparticles stand out as an important class of nanomaterials with wide application areas including environmental catalysis. The use of iron oxide nanoparticles for wastewater treatment has been extensively studied, including their promising potential for full scale environmental remediation [1]. Furthermore, the ability of self-heating under the influence of an alternating magnetic field (AMF) of this kind of materials presents a remarkably advantage to reach greater production yields in shorter residence times [2]. In this sense, the use of magnetic iron oxide nanoparticles for advanced oxidation processes has been widely studied due to their iron ions availability [3].

Here, we have optimized a facile one-pot polyol process to produce a highly efficient 40 nm superparamagnetic iron oxide nanocatalyst (MNC) conformed of aggregated cores of 10 nm. The MNC was fully characterized and tested in the degradation of organic pollutants with an AMF (24 kA/m). Fig 1 shows the experimental set-up for the degradation reaction of two industrially obtained samples: textile industry wastewater (TIW) and landfill leachate (LIX).

Fig. 1. Experimental set-up for the degradation reaction with an AMF. (1)

Inductor, (2) thermostat line, (3) mechanical stirrer, (4) temperature probe,

(5) reactor, (6) inductor insulator, (7) controller, (8) temperature indicator/recorder and (9) capacitors box

MNC under the AMF successfully heated up to 90 ºC (SAR value in Fig.2) and the catalytic performance of this heating method was compared with reactions carried out at 60 and 90 ºC heated in a common thermal reactor. Greater degradation rates were obtained with the increasing temperature and even more when using the magnetic nanocatalyst as heating source. Table I summarizes the decolorization and mineralization yields of the process.

Fig. 2. Heating efficiency (SAR) at 24 kA/m and TEM image of the MNC

TABLE I. YIELDS OF THE ADVANCED OXIDATION OF

INDUSTRIAL WASTEWATERS UNDER AN ALTERNATING

MAGNETIC FIELD

The oxidation ability of the MNC by a Fenton-like reaction was sustained by electron paramagnetic resonance spectroscopy. The oxidation process was successfully enhanced with the alternating magnetic field. Here, it was shown that magnetic induction heating of iron oxide nanocatalyst is a very promising way to reach higher reaction yields for the effective degradation of pollutants from textile industries and solid landfills.

REFERENCES

[1] P. Xu, G.M. Zeng, D.L. Huang, C.L. Feng, S. Hu, M.H. Zhao, C. Lai, Z. Wei, C. Huang, G.X. Xie, Z.F. Liu, “Use of iron oxide nanomaterials in wastewater treatment: A review,” Sci. Total Environ., vol. 424, pp. 1-10, 2012.

[2] W. Wang, G. Tuci, C. Duong-Viet, Y. Liu, A. Rossin, L. Luconi, J.M. Nhut, L. Nguyen-Dinh, C. Pham-Huu, G. Giambastiani, “Induction Heating: An Enabling Technology for the Heat Management in Catalytic Processes,” ACS Catal., vol. 9, pp. 7921-7935, 2019.

[3] J. He, X. Yang, B. Men, D. Wang, “Interfacial mechanisms of heterogeneous Fenton reactions catalyzed by iron-based materials: A review,” J. Environ. Sci. (China), vol. 39, pp. 97-109, 2016.

+




03NEE04-1

Evolution of Multicomponent Structures of

Biopolymer Composites under the Action of Severe

Plastic Deformation Andrei Voznyak

Department of General Technical

Disciplines and Vocational Training

Kryvyi Rih State Pedagogical

University

Kryvyi Rih, Ukraine

[email protected]

Galina Ivanova

Department of General Technical

Disciplines and Vocational Training

Kryvyi Rih State Pedagogical

University

Kryvyi Rih, Ukraine

[email protected]

Igor Dovgoruk

Mechanical Department

Motor Vocational College of Kryvyi Rih

National University

Kryvyi Rih, Ukraine

[email protected]

Currently, great scientific interest is shown in the study of self-organization of multilevel structures, which consist of a large number of interacting elements. Knowing the patterns of evolution of the structure, which take place at different scale levels (nano-, meso and macro-scales), the structure of the system is programmed at each level so that self-organization goes the required way, including the formation of nanostructures or hybrid structures. The latter are formed by combining two or more materials to obtain a superposition of their properties, a new set of physical and functional characteristics or a synergistic effect.

The object of the study was the structural modification of composite materials based on polylactides (PLA) containing fillers of various types (graphite nanoplates, carbon nanotubes). Chain extender Joncryl was used to form polylactide with different chain length and morphology (linear or branched PLA). Polymer-polymer composites based on natural polymers such as PLA and poly(butylene adipate-co-terephthalate) (PBAT) were also studied.

In the present work, equal channel multi angular extrusion (Fig.1) was selected as a solid state extrusion method that affects PLA microstructure through extreme uniform simple shear [1,2]. A peculiarity of equal channel multi angular extrusion compared to equal channel angular extrusion is that several zones of shear deformation are present within one device permitting the accumulation of high plastic deformation per one cycle. Moreover, compared to a pure shear, deformation by a simple shear does not result in final changes of billet shape and dimensions, which favorably distinguishes the process of accumulation of plastic deformation in the latter case. This kind of processing is also able to form a reinforcing structure characterized by enhanced strength and toughness [3-8] without the need for the introduction of nanofillers, the formation of blends, etc. сited above.

It is demonstrated that simple shear deformation implemented in equal channel multi angular extrusion results in formation of an orientation order, an increase in the degree

of crystallinity and the creation of crystals with an increased degree of perfection. The value of the effects achieved depends on the type of PLA morphology. The best result is observed in the case of linear PLA. Modified by equal channel multi angular extrusion linear PLA possess the better combination of strength, modulus and ductility than the branched one. Compared to neat linear PLA, ECMAE-modified linear PLA shows 15, 30, 200 and 50 % increase in tensile strength, Young’s modulus, strain at break and impact strength, respectively. Additionally, the storage modulus shows

an improved thermal stability of PLA modified by equal channel multi angular extrusion. For composites, it is shown that a plastic deformation contributes to significant changes in the crystal structure and morphology of the nanofiller and polymer matrix: there is a significant exfoliation of agglomerates of filler as well as the orientation of the filler and polymer crystals. In the case of polymer-polymer composites, the possibility of forming part of the reinforcing fibers in situ during the deformation process is shown.

Fig. 1. Scheme of equal channel multi angular extrusion

REFERENCES

[1] V.A. Beloshenko, Yu.V. Voznyak, I.Yu. Reshidova, M. Naït-Abdelaziz, F. Zairi, “Equal-channel Angular Extrusion of Polymers,” J. Polym. Res., vol. 20, ID 322, 2013.

[2] V. Beloshenko, Iu. Vozniak, Y. Beygelzimer, Y. Estrin, R. Kulagin, “Severe Plastic Deformation of Polymers,” Mater. Trans., vol. 60, pp. 1192-1202, 2019.

[3] V.A. Beloshenko, V.N. Varyukhin, A.V. Voznyak, Yu.V. Voznyak, “Equa-channel Multiangular Extrusion of Semicrystalline Polymers,” Polym. Eng. Sci., vol. 50, pp. 1000-1006, 2010.

[4] V.A. Beloshenko, A.V. Voznyak, Yu.V. Voznyak, G.V. Dudarenko, “Equa-channel Multiple Angular Extrusion of Polyethylene,” J. Appl. Polym. Sci., vol. 127, pp. 1377-1386, 2013.

[5] V.A. Beloshenko, V.N. Varyukhin, A.V. Voznyak, Yu.V. Voznyak, “Polyoxymethylene Orientation by Equa-channel Multiple Angular Extrusion,” J. Appl. Polym. Sci., vol. 126, pp. 837-844, 2012.

[6] V.A. Beloshenko, A.V. Voznyak, Yu.V. Voznyak, “Effects of Equal-channel, Multiple-angular Extrusion on the Physical and Mechanical Properties of Glassy Polymers,” J. Appl. Polym. Sci., vol. 132, ID 42180, 2015.

[7] V. Beloshenko, Yu. Voznyak, A. Voznyak, B. Savchenko, “New Approach to Production of Fiber Reinforced Polymer Hybrid Composites,” Comp. Part B, vol. 112, pp. 22-30, 2017.

[8] V.A. Beloshenko, A.V. Voznyak, Yu.V. Voznyak, B. Savchenko, “Effects of Orientation Ordering of Low-density Polyethylene-multi-walled Carbon Nanotubes Composites Determined by Severe Plastic Deformation,” Polym. Eng. Sci., vol. 59, pp. 714-723, 2019.




03NEE05-1

The Electrophysical and Morphological Properties

of Hydrothermal Synthesized CuFe2O4 and

CuFe2O4 / Reduced Graphene Oxide Composite

Volodymyr Kotsyubynsky

Vasyl Stefanyk Precarpathian National

University

Ivano-Frankivsk, Ukraine [email protected]

Volodymyra Boichuk


University

Ivano-Frankivsk, Ukraine

[email protected]

Ruslan Zapukhlyak


University


Myroslava Hodlevska


University

Ivano-Frankivsk, Ukraine

[email protected]

Mykola Hodlevskyi


University


Andrii Kachmar


University


Oxide nanopowders are the attractive materials for wide range of applications – from catalysis to electrode materials of charge accumulation devices. The major benefit of oxide electrode, in particular materials with a spinel structure, is chemical stability combined with high redox activity. The successful using these materials is possible only after optimization its morphological and electrophysical proper-ties. The formation of nano-sized metal oxides / carbon composite materials allow to improve electrical conductivity and enhance of the surface redox reactions rate capability due to the improving of charge exchange between the tran-sition metals ions on the surface of oxide nanoparticles and the electrolyte. In this work a comparative study of nano-structured CuFe2O4 ferrite and CuFe2O4 / reduced graphene oxide composites obtained by hydrothermal route was done.

Utrafine copper ferrite was synthesized using hydrother-

mal route using Fe2(SO4)3and CuSO45H2O as a precursors at 150 °C for 10 h. The graphene oxide (GO) colloidal solu-tion prepared by Hummers method was used as additive at oxide-based composite material synthesis (mass ratio of spi-nel phase and reduced graphene oxide (rGO) is 2:1. The cha-racteristic (311) reflex of cubic spinel structure is observed for CuFe2O4 material. The average size of coherent scattering domains (Scherrer approach) is about 14 nm. The halo on XRD patterns of CuFe2O4/rGO material is observed at

2=15-27o and corresponds to (002) reflex of structurally

disordered rGO; the absence of spinel phase reflexes is causes by extremely low size oxide particles.

The inversion degree of CuFe2O4 is close to 1 (Mossbauer spectroscopy data at 90 K) so estimated cation distribution for CuFe2O4 sample is (Fe)A[CuFe]BO4. Mossbauer spectra of CuFe2O4 / rGO material is formed by combination of very broaded sextet and doublet components that correspond to intermediate stage between magnetically ordered (MO) and superparamagnetic (SP) states of the oxide particles. The conditions of MO/SP transition depend on the average particle size, temperature and magnetocrystalline anisotropy. The magnetocrystalline anisotropy constant value for CuFe2O4 is about 0.6∙10

4 J∙m

–3 so SP properties at 90 K

will keep for particles with an average sizes less than 8 nm.

The pore size distribution for synthesized materials was calculated using DFT analysis of N2 adsorption-desorption isotherm at 77 K. CuFe2O4 has a mesoporous structure with pore sizes in a range of 3-20 nm and the maxima at about 5 nm. CuFe2O4/rGO has mesoporous structure too with small amount of micropores. BET specific surface area of CuFe2O4 and CuFe2O4/rGO samples are 82 and 356 m

2/g.

The specific electrical conductivity (SEC) for CuFe2O4

and CuFe2O4 / rGO increase with the frequency enlarging in a range of 25-200

оС. SEC for both samples increase to 125

oC

with the next downturn to 200oC due thermal scattering of

carriers by acoustic phonons when most hopping process are activated. The analysis of impedance spectra and the selection of equivalent electrical circuit (EEC) allow to obtain the information about charge transfer mechanisms. The best fitting results for CuFe2O4 were obtained with Rg-(RH-CPE) scheme but for rGO-contained material the additional series (RL-CPE) chain was added (Rg corresponds to resistance of separate particles when RH and RL are corresponding quantities for the grain boundary). Constant phase element (CPE) were used instead of pure capacitances to taking into account high morphological and electrical inhomogeneity of the samples. The common hydrothermal synthesis of CuFe2O4 phase and GO fragments reduction caused the formation of nanocomposite CuFe2O4/rGO particles with respectively lower inner resistance and the presence of two types of intergrain boundaries– between oxide and rGO components into the particles and between particles. The activation energies of carrier hopping mobility into oxide grains for pure CuFe2O4 (0.135 eV) is respectively lower comparatively to spinel grains in CuFe2O4 / rGO sample (0.168 eV) that is caused smaller particle size of the spinel phase in the composite material. The activation energies of grain boundary hopping for CuFe2O4 is more than twice as high as CuFe2O4 / rGO powder (0.229 and 0.111 eV, respectively) due charge transport optimization in two-phase particles. The activation energies of charge transferring between the agglomerates of CuFe2O4 / rGO interconnected of rGO fragments is about 0.262 eV when SEC of that transfer have a minimal values.






03NEE06-1

Application of Nano Materials for the Treatment of

Produced Water

Kingsley Tamunokuro Amakiri, Athanasios Angelis-Dimakis, Marco Molinari Department of Chemical Sciences, School of Applied Sciences, University of Huddersfield

United Kingdom

The Application of Nanotechnology-based systems offer

an inexpensive alternative for developing countries where the facilities needed for water treatment are lacking or non-existent. These are low-energy systems or processes that use nanocomposite materials to reduce and/or remove contaminants in water. Phosphorus-doped TiO2 nanoparticles with visible light activity were prepared by sol-gel method by using Ti(IV) isopropoxide and phosphoric acid as precursors.

The structural and chemical properties of the phosphate-coated P-TiO2 nanoparticles were controlled by changing the concentration of H3PO4 during the coating process. X-ray diffraction results showed complete conversion of the precursor into oxide. More than 90% of TiO2 formed was present as anatase. FTIR, UV-Vis absorption spectroscopy, SEM. showed well-resolved nano-sized particles with more than 70% lying in the range of a few nanometer to 10 nm. The powder has been used to study photocatalytic degradation of Polycyclic aromatic hydrocarbons (PAHs) in Oilfield produced water.




03BA01-1

The Behaviors of Non-persistent Plasmonic

Nano-architectures

Valerio Voliani

Center for Nanotechnology @NEST

Istituto Italiano di Tecnologia

Pisa, Italy [email protected]

Noble metal nanomaterials hold the promise to shift the current medical paradigms for the management of cancer and infectious diseases due to their peculiar chemical, physical and physiological behaviors [1]. Despite the massive efforts, treatments based on inorganic nanomaterials are mainly at the preclinical stage, due to the body persistence issue.

[2]

Indeed, non-biodegradable materials unacceptably persist within excretion system organs for long-term after administration [2].

Fig. 1. Cartoon reporting the TEM image of the biodegradation of the

ultrasmall-in-nano architectures to excretable building blocks in a cancer cell

A groundbreaking advance to jointly combine the appealing features of plasmonic nanomaterials with their excretion relies on the ultrasmall-in-nano approach [1, 3]. The most recent progresses in the design, production and application of ultrasmall-in-nano architectures able to escape from the organism after the designed action will be discussed together with their biokinetics and biosafety [4-7].

The research leading to these results has received funding

from AIRC under MFAG 2017 – ID 19852 project – P.I.

Voliani Valerio.

REFERENCES

[1] D. Cassano, S. Pocoví-Martínez, V. Voliani, “Ultrasmall-in-Nano Approach: Enabling the Translation of Metal Nanomaterials to Clinics,” Bioconjug. Chem., vol. 29, pp. 4-16, 2018.

[2] Y. Vlamidis, V. Voliani, “Bringing Again Noble Metal Nanoparticles to the Forefront of Cancer Therapy,” Front. Bioeng. Biotechnol., vol. 6, ID 143, 2018.

[3] D. Cassano, A.-K. Mapanao, M. Summa, Y. Vlamidis, G. Giannone, M. Santi, E. Guzzolino, L. Pitto, L. Poliseno, R. Bertorelli, V. Voliani, “Biosafety and Biokinetics of Noble Metals: The Impact of Their Chemical Nature,” ACS Appl. Bio Mater., vol. 2, pp. 4464-4470, 2019.

[4] D. Cassano, M. Summa, S. Pocoví-Martínez, A.-K. Mapanao, T. Catelani, R. Bertorelli, V. Voliani, “Biodegradable Ultrasmall‐in‐Nano Gold Architectures: Mid‐Period In Vivo Distribution and Excretion Assessment,” Part. Part. Syst. Charact., vol. 36, ID 1800464, 2019.

[5] D. Cassano, M. Santi, F. D’Autilia, A. K. Mapanao, S. Luin, V. Voliani, “Photothermal Effect by NIR-responsive Excretable Ultrasmall-in-nano Architectures,” Mater. Horiz., vol. 6, pp. 531-537, 2019.

[6] M. Santi, A. K. Mapanao, D. Cassano, Y. Vlamidis, V. Cappello, V. Voliani, “Endogenously-Activated Ultrasmall-in-Nano Therapeutics: Assessment on 3D Head and Neck Squamous Cell Carcinomas,” Cancers, vol. 12, ID 1063, 2020.

[7] A.K. Mapanao, G. Giannone, M. Summa, M.L. Ermini, A. Zamborlin, M. Santi, D. Cassano, R. Bertorelli, V. Voliani, “Biokinetics and clearance of inhaled gold ultrasmall-in-nano architectures,” Nanoscale Adv., vol. 2, pp. 3815-3820, 2020.




03BA02-1

Composite on the Base of Natural Silicates (Zeolite,

Kaolinite, Montmorillonite) and Plant Raw Material

for Food and Cosmetics Purposes:

Nanocomposites and Nanohybrids V. Paientko

Chuiko Institute of Surface Chemistry

NAS of Ukraine


N. Liedienov

State Key Laboratory of Superhard

Materials, International Center of

Future Science of Jilin

Changchun, China

Donetsk Institute for Physics and

Engineering named after O. O. Galkin,

NASU

[email protected]

V. Kostur

Limited Liability Company «AX

MINERAL»

Lviv Ukraine

[email protected]

A. Matkovsky

Chuiko Institute of Surface Chemistry

NAS of Ukraine

Kyiv, Ukraine

[email protected]

A. Pashchenko

State Key Laboratory of Superhard

Materials, International Center of

Future Science of Jilin

Changchun, China

Donetsk Institute for Physics and

Engineering named after O. O. Galkin,

NASU

[email protected]

V. Zadorozniy

Limited Liability Company «AX

MINERAL»

Lviv Ukraine

[email protected]

L. Babenko

N.G. Kholodny Institute of Botany

NAS of Ukraine

Kyiv, Ukraine

[email protected]

O. Yesypchuk

Naturel Medical Aesthetic

Chernivtsi, Ukraine

[email protected]

The

structure peculiarity and disposivity of natural silicates are important properties due to which these minerals are used in cosmetology. Also their abrasivity, adsorptivity and colloidal ones create preconditions for use of silicates as carriers of biologically active substances (BAS), including vitamins and cosmetic fillers.

The aluminosilicates have different structure and absorptivity relatively BAS, providing number of their using for creation of composites. In this work, clays of different structure and clinoptiolite (Sokyrnytsia, Ukraine) have been used. These materials are environmentally friendly, low cost and certified as food additives. The porosity and absorptivity of clinoptilolite (rough surface, pores and channels, windows) conditional by it frame structure. In zeolite, silica and alumina tetrahedral are interconnected by oxygen atoms, forming 8- and 10-membered rings, so-called entrance "windows" into the channels.

The kinetics of BAS release is controlled by the chemical nature of the surface and by the porosity of the carrier. Changing porosity and the surface area by using of aluminosilicate matrixes of different structures as carriers allow controlling the release of biologically active substances (BAS), prolonging the term of the effective using. In addition to that fact these carriers allow to transport BAS. They have biocompatibility and bioavailability without causing allergic reaction.

Thus, the composite materials of clay / clinoptiolite / silica / vegetable raw materials, where the nature of the inorganic component and the presence / absence of solvent are varied, have been obtained. The dependence of BAS allocation on the structure and composition of the synthesized composite has been established




03BA03-1

Rescuing Neuroblastoma Cells from Oxidative

Stress Using Naturally-derived Graphene Quantum

Dots

Jyoti Ahlawat, Mahesh Narayan

Department of Chemistry and Biochemistry,

The University of Texas at El Paso

USA [email protected]

Graphene Quantum Dots (CQDs) has demonstrated high potency to mitigate neuronal oxidative stress and related pathologies, including Parkinson's disease (PD). However, the application of GQDs is limited due to their inability to cross the Blood-Brain Barrier (BBB) without disrupting tight junctions' structural integrity. Here, we introduce naturally-derived GQD, using a very easy and facile synthesis method,

for easy passage across the BBB and display prophylactic activity. Due to the increasing evidence of the role played by anthropogenic toxins to initiate PD, the study employs rotenone, a known pesticide, as the model causative species and SH-SY5Y neuroblastoma cell line as the model cell line. Our study illustrates the neuroprotective efficacy of these as -synthesized GQDs.




03BA04-1

Composite of Cobalt Ferrite Nanoparticles

Substituted with Zinc as Promicing Tool for

Leukemia Treatment Anna Motorzhina

Institute of Physics, Mathematics & IT


University


Sonja Jovanovic


Vinča Institute of Nuclear Sciences -

National Institute of thе Republic of

Serbia, University of Belgrade,

Belgrade, Serbia [email protected]

Stanislav Pshenichnikov



University


Kateryna Levada



University

Kaliningrad, Russia

[email protected]

Marija Vukomanovic

Advanced Materials Department

Jožef Stefan Institute

Ljubljana, Slovenia [email protected]

Valeria Rodionova



University


The vast scope of biomedical applications, such as MRI,

hyperthermia, targeted drug delivery etc made composite

magnetic nanoparticles particulary interesting for research.

Composite of cobalt ferrite nanoparticles substituted with

zinc (Сo0,5Zn0,5Fe2O4) are in addition to all chemically-stable

and have custom magnetic properties [1]. Nanoparticles were

covered with dihydrocaffeic acid and gold nanoparticles with

arginin for the achievement of hydrophobic and antibacterial

effects which are essential for tests in vitro.

Among all types of childeren’s and youngs’ cancer

almost 40% cases are leukemia - For obtaining the

information about possibility of using Сo0,5Zn0,5Fe2O4

nanoparticles in biomedicine we investigated its influence on

proliferative activity of human leukemic Jurkat cells

(Russian Cell Culture Collection, Institute of Cytology

RAS). Cell viability was controlled by Countess Automated

Cell Counter (Invitrogen, USA) with Trypan blue dye

(Invitrogen, USA). The cells were cultured in RPMI 1640

(Sigma, USA) suspension, supplemented with 10% fetal

bovine serum (Sigma, USA), 0,3 mg/ml L-glutamine (Sigma,

USA) and 1% penicillin and streptomycin. The cells were

incubated in a 5% CO2 and 37 °С humidified atmosphere.

The cytotoxicity of Сo0,5Zn0,5Fe2O4 nanoparticles on

Jurkat cells was measured using a WST-1 test. The assay is

based on the measuring the optical density difference

between light red tetrazolium salt WST-1 (Roche

Diagnostics GmbH, Germany) converting by viable cells

into the yellow formazan derivative [2].

Three concentrations of Сo0,5Zn0,5Fe2O4 nanoparticles:

10, 50 and 100 μg/ml, were investigated after 2, 4, 6, 8 and

24 h exposure in cell suspension. 96 well microplates with

experimental suspensions was incubated a 5% CO2 and 37

°С humidified atmosphere. During the last 2 h of exposure,

10 μl of WST-1 reagent was added. Absorbance was

measured at 450 nm in a microplate reader.

Fig.1 shows that statistically the lowest proliferative activity

cell culture has after 24 h exposure with Сo0,5Zn0,5Fe2O4

nanoparticles. The comparison of the viability of Jurkat cells

after exposure with various concentrations of Сo0,5Zn0,5Fe2O4

nanoparticles shows that cytotoxicity of 100 μg/ml

concentration was the highest (Fig. 2).

Fig. 1. Effect of exposure time and Сo0,5Zn0,5Fe2O4 nanoparticles

concentrations on viability of Jurkat cells.Viabilities were assessed by the WST-1 assay. The relative viability after exposures is presented as

percentage compared to the control at the same time point. Results shown

are mean±SD fron triplicate exposures.

Fig. 2. The relative viability of Jurkat cells after 24 h exposure with

Сo0,5Zn0,5Fe2O4 nanoparticles. Data is presented compared to the control

at the same time point as percentage. Results shown are mean±SD fron triplicate exposures, **: P < 0,01; ***: P < 0,001 (Student’s T-test).

In summary, composite of cobalt ferrite nanoparticles

substituted with zinc covered with dihydrocaffeic acid and

gold nanoparticles with arginin at a concentration of 100

μg/ml are optimal for use in biomedicine as a drug for T-

lymphoblastic leukemia.

REFERENCES

[1] G. Muscas, S. Jovanovic, M. Vukomanovic, M. Spreitzer, D. Peddis,

“Zn-doped cobalt ferrite: Tuning the interactions by chemical

composition” J. Alloy. Compd., vol. 796, pp. 203-209, 2019.

[2] M.R. Katika, P.J.M. Hendriksen, H. van Loveren, A. Peijnenburg,

“Exposure of Jurkat cells to bis (tri-n-butyltin) oxide (TBTO) induces transcriptomics changes indicative for ER- and oxidative stress, T cell

activation and apoptosis”, Toxicol. Appl. Pharmacol., vol. 254, pp.

311-322, 2011.




03BA05-1

Effect of Piezoelectric Composites on the Adhesion

and Migration of Neuronal Stem Cells

Valentina Antipova

Laboratory of Novel Magnetic

Materials


University

Kaliningrad, Russia

[email protected]

Yilin Han

Department of Neuroscience,

Biomedical Centre

Uppsala University

Uppsala,Sweden

[email protected]

Abdulkarim Amirov


Materials


University

Kaliningrad, Russia

[email protected]

Elena N. Kozlova

Department of Neuroscience,

Biomedical Centre

Uppsala University

Uppsala,Sweden

[email protected]

Kateryna Levada


Materials


University

Kaliningrad, Russia

[email protected]

Valeria Rodionova


Materials


University

Kaliningrad, Russia

[email protected]

Application of physical factors as electrical stimulation, variable magnetic field stimulation and mechanical stretching important during embryogenesis and therefore can be applicable for stem cell differentiation, that recapitulates normal development/differentiation.

In this work magnetoelectic compositeson are used as a model of a biological interface with interconnected piezoelectric and ferromagnetic properties. Magnetoelectric compositeson are polymer matrix that containing inside particles. Boundary cap neural crest stem cell (bNCSCs), which were kindly provided by Professor Elena Kozlova, Uppsala University, Department of Neuroscience, were selected as the biological object on which various compositeson were tested. Boundary cap neural crest stem cell culture is a transient neural crest-derived group of cells located at the dorsal root entry zone (DREZ) that have been shown to differentiate into sensory neurons and glia in vivo and in vitro [1].To produce the composites, we used a biocompatible polymer Polyvinylidene difluoride (PVDF) and its copolymers polyvinylidene fluoride-co-trifluoroethylene (PVDF-TrFE), organic solvent Dimethylformamide (DMF) and two types of magnetic particles (Fe3O4, CoFe2O4). In this study we elucidated the role of magnetoelectic compositeson to support bNCSCs and analyze how different compositeson manufacturing techniques affect its electroactivity.

The processing conditions of PVDF and its copolymer affect the phase content, morphology and electroactivity [2]. The addition of magnetic particles to the polymer matrix improves the formation and stabilization of the electroactive phase of the PVDF [3, 4]. By varying the concentration of magnetic particles, their type and different methods of their distribution over the polymer base, we were able to obtain substrates with different types of morphology and different degrees of electroactivity. Culturing bNCSC on PVDF-compositeson showed poor adhesion and neurite growth, which may be associated with low adhesive properties of the substrate due to the high degree of hydrophobicity of the polymer base of compositeson. According to the results of fluorescence analysis, a small number of elongated cells with

growing neurites were found, which is a confirmation of the low adhesive properties of the substrate (Fig.1).

Fig. 1. β3-tubulin (green) expressing bNCSCs (red) growing on PVDF-

compositeson (x20). Blue — Hoechst nuclear stain; arrow indicates

growing neurite. Bar = 25 μm

REFERENCES

[1] J. Hjerling-Leffler, F. Marmigère, M. Heglind, et al., “The Boundary Cap: a Source of Neural Crest Stem Cells that Generate Multiple Sensory Neuron Subtypes,” Development (Cambridge, England), vol. 132(11), pp. 2623-2632, 2005.

[2] J.S. Nunes, A. Wu, J. Gomes, V. Sencadas, P.M. Vilarinho, S. Lanceros-Mendez, “Relationship Between the Microstructure and the Microscopic Piezoelectric Response of the Alpha- and Beta-Phases of Poly(vinylidene Fuoride),” Appl. Phys A, vol. 95, pp. 875-880, 2009.

[3] V.M. Andrade, A. Amirov, D. Yusupov, et al., “Multicaloric Effect in a Multiferroic Composite of Gd5(Si,Ge)4 Microparticles Embedded into a Ferroelectric PVDF Matrix,” Sci. Rep. vol. 9, ID 18308, 2019.

[4] Y. Li, C. Liao, S.C. Tjong, “Electrospun Polyvinylidene Fluoride-Based Fibrous Scaffolds with Piezoelectric Characteristics for Bone and Neural Tissue Engineering,” Nanomaterials, vol. 9, ID 952, 2019.



Sumy, Ukraine, Nov. 9-13 2020

03TM01-1

Vortex States in Core-shell Ferroelectric

Nanoparticles for Multi-bit Memory Anna N. Morozovska

Institute of Physics, National Academy

of Sciences of Ukraine


Viktoriia V. Tulaidan


of Kyiv

Kyiv, Ukraine

[email protected]

Eugene A. Eliseev

Institute for Problems of Materials

Science, National Academy of Sciences

of Ukraine


Victor Yu. Reshetnyak


of Kyiv

Kyiv, Ukraine

[email protected]

Riccardo Hertel

Université de Strasbourg, CNRS,

Institut de Physique et Chimie des

Matériaux de Strasbourg

Strasbourg, France [email protected]

Dean R. Evans

Air Force Research Laboratory,

Materials and Manufacturing

Directorate, Wright-Patterson Air

Force Base

Ohio, USA

[email protected]

The fundamental question whether the structure of curled topological polarization states, such as ferroelectric vortices, can be controlled by the application of an irrotational electric field is open. Recently we studied the influence of irrotational external electric fields on the formation, evolution, and relaxation of ferroelectric vortices in spherical nanoparticles. In the framework of the Landau-Ginzburg-Devonshire approach, we performed finite element modeling of the polarization behavior in a ferroelectric barium titanate core covered with a “tunable” paraelectric strontium titanate shell placed in a polymer or liquid medium [1].

A stable two-dimensional vortex is formed in the core after a zero-field relaxation of an initial random or poly-domain distribution of the polarization, where the vortex axis is directed along one of the core crystallographic axes. Subsequently, sinusoidal pulses of a homogeneous electric field with variable period, strength, and direction are applied. The field-induced changes of the vortex structure consist in the appearance of an axial “kernel” in the form of a prolate nanodomain, the growth of the kernel, an increasing orientation of the polarization along the field, and the onset of a single-domain state.

Fig. 1. Spherical core-shell nanoparticles with a vortex polarization and

axial dipolar kernel. Reprinted from [1].

After removal of the electric field, the vortex recovers spontaneously; but its structure, axis orientation, and vorticity can be different from the initial state. As a rule, the final state is a stable three-dimensional polarization vortex with an axial dipolar kernel, which has a lower energy compared to the initial purely azimuthal vortex. The nature of this counterintuitive result is a significant gain of the negative Landau energy in the axial region of the vortex by the formation of a kernel, which is only partly compensated by an increase in positive energy of the depolarization field,

polarization gradient, and elastic stress for a vortex with a prolate single-domain kernel.

The vortex states with a kernel possess a manifold degeneracy, appearing from three equiprobable directions of vortex axis, clockwise and counterclockwise directions of polarization rotation along the vortex axis, and two polarization directions in the kernel. This multitude of vortex states in a single core is promising for applications of core-shell nanoparticles and their ensembles as multi-bit memory and logic units. A rotation of the vortex kernel over a sphere, which is possible for the core-shell nanoparticles in a soft matter medium with a controllable viscosity, may be used to imitate qubit features. This ability to control the nanoparticle’s core polarization by the shell screening, in combination with external irrotational electric fields could be attractive for new applications, such as multi-bit memory and logic units.

Another interesting aspect is that the classical behavior of the vortex axis with a conductive kernel can simulate a “qubit” at room temperature, since it formally appears that some basic properties of qubits necessary for a quantum computation can be attributed to the vortex states “±1” revealed in [1]. These possibilities are sketched in Fig. 1. However, one should realize that the long-range electrostatic interaction between the core-shell ferroelectric nanoparticles is different from a “true” entanglement of e.g. photons, because photons can be entangled on a macroscopic scale [2], whereas the coupling between the nanoparticles decays with increasing distance due to the attenuation of electrostatic fields.

ACKNOWLEDGEMENTS

A.N.M. acknowledges EOARD project 9IOE063 and related STCU partner project P751.

REFERENCES

[1] A.N. Morozovska, E.A. Eliseev, R. Hertel, Y.M. Fomichov, V. Tulaidan, V.Yu. Reshetnyak, D.R. Evans, “Electric Field Control of Three-Dimensional Vortex States in Core-Shell Ferroelectric Nanoparticles” (http://arxiv.org/abs/2004.00962).

[2] M.A. Nielsen, I.L. Chuang, Quantum Computation and Quantum Information, Cambridge University Press., 2010.

http://arxiv.org/abs/2004.00962

https://en.wikipedia.org/wiki/Quantum_Computation_and_Quantum_Information_(book)

https://en.wikipedia.org/wiki/Quantum_Computation_and_Quantum_Information_(book)

https://en.wikipedia.org/wiki/Cambridge_University_Press




03TM02-1

Electronic and Optical Properties of 1T’-ReS2

Graphene van der Waals Heterostuctures

Amretashis Sengupta

University of North Bengal, Dist. Darjeeling

WB – 734 013, India

[email protected]

In recent years, ReS2 a layered transition metal dichalcogenide (TMDC) with a highly stable 1T’ polytype, possesing anisotropic carrier conductance, and a direct band-gap independent of the number of layers, has amassed significant interest. [1]-[3] In this regard, the interface of ReS2 with graphene becomes worthy of investigation, given the possibility of all 2D materials based flexible devices in near future.

Here, we investigate the electronic and photo-absorption properties of van der Waals heterostructures (vdWh) consisting of graphene and 1T’-ReS2, with density functional theory (DFT) calculations. For our studies, we considered bilayer 1T’ ReS2 – graphene supercells having two distinct Moire patterns labelled P-I and P-II, as shown in Fig. 1.

The density functional theory (DFT) calculations with the GGA-PBE exchange and correlation functional, were carried out with the Quantum ESPRESSO 6.0 code. [4] We used Troullier-Martins type norm-conserving FHI pseudopotentials for our calculations, with a plane-wave cut-off energy of 60Ry and a 8x8x1 Monkhorst-Pack k-grid sampling. The supercells were optimized with the Broyden Fletcher Goldfarb Shanno (BFGS) method with Grimme’s DFT-D2 correction applied to incorporate the van der Waals interactions. The optical properties are calculated with the epsilon.x package included within the ESPRESSO suite. The optimized vdWh were studied for their electronic properties such as bandstructure, density of states, electron localization, electrostatic potential and for optical properties as the dielectric function, optical absorption and joint density of states.

The DFT calculations show an optimized interlayer distance for the P-I pattern was calculated to be 3.47Å, while the same for the P-II pattern was 3.48Å. In terms of stability the second configuration (P-II) was energetically more favourable as compared to P-I by about 0.12eV. Semi-metallic nature of the resultant vdWh was observed with a small number of states appearing near the fermi level owing to the contributions from the graphene layer, as seen in Fig. 2. From the electron localization iso-surface plots in Fig. 2, the presence of significant electron-gas like carrier distribution among the graphene and ReS2 sheets are also seen. These electron-gas like features are really pronounced near the bottom chalcogen atoms, with some degree of screening on the top chalcogen atoms.

The optical spectra, as presented in Fig. 2, showed an absorption in the range 0.5-3% mostly in the visible-UV range. It was also observed that the relative orientation between the graphene and 1T’ -ReS2 sheet had only very minimal effect on the absorption spectra.

Fig. 1. Top and side views of the graphene-ReS2 vdWh supercell. The

different Moire patterens are labelled P-I and P-II.

Fig. 2. (a) Optical absorption spectra (b) density of states plot showing

contributions from graphene and ReS2 layers and (c) electron localization iso-surface plots of the two vdWh under study.

REFERENCES

[1] S. Tongay, et al., “Monolayer behaviour in bulk ReS2 due to electronic and vibrational decoupling,” Nat. Commun., vol. 5, pp. 1-6, 2014.

[2] C.M. Corbet, C. McClellan, A. Rai, S.S. Sonde, E. Tutuc, S.K. Banerjee, “Field effect transistors with current saturation and voltage gain in ultrathin ReS2,” ACS Nano, vol. 9, no. 1, pp. 363-370, 2015.

[3] N.R. Pradhan, et al., “Metal to Insulator Quantum-Phase Transition in Few-Layered ReS2,” Nano Lett., vol. 15, no. 12, pp. 8377-8384, 2015.

[4] P. Giannozzi, et al., “QUANTUM ESPRESSO: a modular and opensource software project for quantum simulations of materials,” J. Phys. Condens. Matter, vol. 21, no. 39, ID 395502, 2009.




03SAMA01-1

4D Printing using Anisotropy of Extrusion Type

Additive Manufacturing

Keun Park

Department of Mechanical System

Design Engineering

Seoul National University of Science

and Technology

Seoul, Republic of Korea [email protected]

Bona Goo


Design Engineering


and Technology


Chae-Hee Hong


Design Engineering


and Technology


Additive manufacturing (AM), also known as three-dimensional (3D) printing, has extended its application area from conventional rapid prototyping (RP) to the direct fabrication of functional parts. A unique extension of AM is 4D printing, which adds changes of shapes or properties over time to conventional 3D printing [1]. The most 4D printing methods use shape memory polymer (SMP) that responds to external stimuli by changing their shapes and physical properties [2]. Another application of 4D printing has been based on the printing multi-materials that have different swelling properties [3].

This study aims to develop a 4D printing method using a single thermoplastic polymer and a personal fused deposition modeling (FDM) printer. Acrylonitrile butadiene styrene (ABS), which does not have a shape memory function, was used in 4D printing. To differentiate the deformation behavior in a printed part with a single material, we used the thermal anisotropy of FDM-printed parts [4]. That is, the printing paths were controlled by printing the transverse and longitudinal layers consecutively. This intentional anisotropy was then used to induce bending deformation when an appropriate heat treatment was followed [5].

Fig. 1. 4D printing of a 2D flower-shape: (a) Printing path designs for the

flower shape; (b) Shape changes of the flower-shape specimen according to the heating time

These directional printing paths were applied to 2D-to-3D shape transformation. Figure 1a shows the longitudinal

and transverse printing paths for a 2D flower shape. Here, the printing paths were generated for a base region that was shaded in Fig. 1. An FDM type 3D printer (Cubicon Single, Cubicon Inc., Korea) was used in AM. The layer thickness was also set to 0.2 mm, and a total of eight layers were laminated to build a 1.6 mm thickness. Three transversely printed layers and five longitudinally printed layers were consecutively laminated based on these printing paths. As a thermal stimulus, heat treatment was performed using an electric furnace (DHG-9070A, NeuronFit Co. Ltd., Korea). The furnace was preheated to 150 °C, and heat treatment was performed for 15 min.

Figure 1b shows the sequential shape changes of the flower shape with an increase in the heating time. It was observed that one end of the flower began to bend after seven minutes of heating. This shape transformation indicates that the specimen was heated enough to initiate thermal deformation by overcoming its own weight. That is, the length increase of the lower region (transversely printed) and the length decrease of the upper region (longitudinally printed) caused a bending deformation. This bending deformation continued with an increase in the heating time, and the 2D flower specimen changed into a 3D flower shape.

ACKNOLEDGEMENT

This research was financially supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT, Republic of Korea (Grant number: 2019R1A2C1002799).

REFERENCES

[1] S. Tibbits, “4D Printing: Multi-material Shape Change,” Archit. Des., vol. 84, pp. 116-121, 2014.

[2] S. Li, W. M. Huang, “Mechanisms of the Multi-shape Memory Effect and Temperature Memory Effect in Shape Memory Polymers,” Soft Matter., vol. 6, pp. 4403-4406, 2010.

[3] Q. Zhang, K. Zhang, G. Hu, “Smart Three-dimensional Lightweight Structure Triggered from a Thin Composite Sheet via 3D Printing Technique,” Sci. Rep., vol. 6, pp. 1-8, 2016.

[4] S.H. Ahn, M. Montero, D. Odell, S. Roundy, P.K. Wright, “Anisotropic Material Properties of Fused Deposition Modeling ABS,” Rapid Prototyp. J., vol. 8, pp. 248-257, 2002.

[5] B. Goo, C.H. Hong, K. Park, “4D Printing Using Anisotropic Thermal Deformation of 3D-Printed Thermoplastic Parts,” Mater. Des., vol. 188, ID 108485, 2020.




03SAMA02-1

Extending the Use of Lignocellulosic Biomass in

Additive Manufacturing Technology

Mohd Shaiful Sajab

Reseach Center for Sustainable Process Technology (CESPRO)

Universiti Kebangsaan Malaysia

Selangor, Malaysia [email protected]

Denesh Mohan

Reseach Center for Sustainable Process Technology (CESPRO)

Universiti Kebangsaan Malaysia

Selangor, Malaysia [email protected]

The production of naturally derived polymers for additive manufacturing (AM) materials is promising. Despite the essential role of lignin and cellulose in the next-generation of polymer nanocomposite, Malaysia industry is yet to be fully equipped with suitable technology in the large-scale fractionation of cellulose from our underutilized biomass. This complication was highly associated with the limited yield of cellulose, under-utilized byproducts and highly selective on water dispersible polymer matrices. The inability to disperse cellulose and lignin after fractionation process is a major drawback of converting biopolymer from biomass completely. Whereas, the typical utilization of nanocellulose as reinforcing nanofiller for the synthetic polymer is mostly required high temperature during polymerization. Cellulose is the most abundant biopolymer that has many favourable properties that have been continuously concentrated on in recent years to be used in AM products (see Fig. 1) [1].

Briefly, fractionation process of nanocellulose and lignin will undergo modification method of organosolv, catalytic oxidation and mechanical methods. The isolated nanocellulose has been modified by acetylation or graft copolymeric in the interest of chemical compatibility with the nonwater-based polymer [2]. Eventually, the compatibility of the lignin acrylate and acetylated nanocellulose as reinforced stereolithography materials will be tested through series of chemical, physical and mechanical testing through the standard fabricated sample [3].

Fig. 1. Possible pathway of extending cellulose-based polymer for

sustainable AM

Nevertheless, recently, the advancement of 3D printing has brought about a cost-effective and versatile 3D printing consists of layers of material deposited directly from solution in a volatile solvent. Known as liquid deposition modeling (LDM), this relatively new technology promises the production of freeform structures using a computer-controlled from a wide range of materials. LDM allows direct fabrication of low-cost architectures in a versatile technique. However, similar to most of the 3D printing available, LDM still exhibits difficulty in achieving nano resolution. In the past years, the fabrication of biodegradable ink from nanocellulose has been attracted to the various industry especially in the use of biomedical applications [4].

REFERENCES

[1] D. Mohan, Z.K. Teong, A.N. Bakir, M.S. Sajab, H. Kaco, “Extending Cellulose-Based Polymers Application in Additive Manufacturing Technology: A Review of Recent Approaches,” Polymers, vol. 12(9), ID 1876, 2020.

[2] D. Mohan, M.S. Sajab, H. Kaco, S.B. Bakarudin, M. Noor, “3D Printing of UV-Curable Polyurethane Incorporated with Surface-Grafted Nanocellulose,” Nanomaterials, vol. 9(12), ID 1726, 2019.

[3] F. Ibrahim, D. Mohan, M.S. Sajab, S.B. Bakarudin, H. Kaco, “Evaluation of the Compatibility of Organosolv Lignin-graphene Nanoplatelets with Photo-curable Polyurethane in Stereolithography 3D Printing,” Polymers, vol. 11(10), ID 1544, 2019.

[4] D. Mohan, N.F. Khairullah, Y.P. How, M.S. Sajab, H. Kaco, “3D Printed Laminated CaCO3-Nanocellulose Films as Controlled-Release 5-Fluorouracil,” Polymers, vol. 12(4), ID 986, 2020.




03SAMA03-1

Additive Manufacturing of Brass Alloys

Vladimir Popov

Israel Institute of Metals

Technion R&D Foundation

Haifa, Israel [email protected]

Alex Fleisher




Evgeny Strokin




Aleksey Kovalevsky




Brass is a binary alloy composed of copper and zinc, which is widely used in manufacturing faucets and water taps. Brass is valued for its excellent properties such as: workability; hardness; corrosion resistance; anti-bacterial properties; good heat and electrical conductivity. However, additive manufacturing of brass alloys is a challenging task. There are limited reported data in scientific literature on brass printing, and most of them used powders with low zinc content [1], [2].

In the presented research several experiments of additive manufacturing (AM) of brass powder with high zinc content were conducted. At that there were tried the main AM techniques – Selective Laser Melting (SLM); Electron Beam Melting (EBM); and Binder Jetting [3].

It was found the several issues that should be taken into account for each specific process:

a) The raw powder selection: For the EBM process it is crucial that the powder size should be bigger than 50 microns, without satellites. The low melting temperature of Zn might cause its evaporation during the EBM process. For EBM and Binder Jetting process the issue of powder removal from as-built parts is a rather challenging (or even impossible) task;

Fig. 1. Raw material for powder-based additive manufacturing: a – brass

powder; b – blended powder 70% of copper and 30% of brass.

b) In-situ alloying: For some applications the blended powder (copper + brass; or copper +zinc) can be used for in-situ alloying in SLM process. The SLM-printed alloy corresponds to brass specification. However, the difference in melting points of copper and zinc causes zinc evaporation and porosity in the SLM-printed parts;

c) Oxidation: brass powder is prone to oxidation that results in high porosity level in printed parts. It is crucial for post-processing of “green” parts produced by Binder Jetting (see Fig. 2), and also for homogeneous melting during EBM and SLM processes.

Fig. 2. Brass “green” samples manufactured by Binder Jetting Printing

Fig. 3. SLM manufacturing of brass samples from blended Cu/Zn powder:

1 – powder; 2 – printed brass samples; 3 – building platform; 4 – rake.

The performed study provides design guidelines in additive manufacturing of brass components using various powder materials, and the main AM techniques. The study includes problematic issues specification; troubleshooting; and technological recommendations.

REFERENCES

[1] C. Yang, Y.J. Zhao, L.M. Kang, D.D. Li, W.W. Zhang, L.C. Zhang, “High-strength Silicon Brass Manufactured by Selective Laser Melting,” Mater. Lett., vol. 210, pp. 169-172, 2018.

[2] Z. Szakál, A. Kári-Horváth, T. Pataki, M. Odrobina, “The Mechanical Properties of 3D Printed CuZn28 Brass Specimens with Different Orientations,” Int. J. Eng. Manag. Sci., vol. 4, no 1, pp. 253-259, 2019.

[3] A. Katz-Demyanetz, V. Popov, A. Kovalevsky, D. Safranchik, A. Koptyug, “Powder-bed Additive Manufacturing for Aerospace Application: Techniques, Metallic and Metal/Ceramic Composite Materials and Trends,” Manuf. Rev., vol. 6, ID 5, 2019.




03SAMA04-1

Evaluation of 3D Printed Scaffolds for Tissue

Engineering

Anniina Palojarvi

Microfabrication Lab

Finnadvance

Oulu, Finland [email protected]

Prateek Singh

Bone Lab

Finnadvance

Oulu, Finland

[email protected]

Tuan Hoang Nguyen

Microfabrication Lab

Finnadvance


Minna Kihlström

Bone Lab

Finnadvance


Three-dimensional (3D) printing, or specifically additive manufacturing, has been promising in rapid fabrication of complex structures in various use cases. Tissue engineering being one of them, has harnessed it’s potential in enabling rapid prototyping of scaffolds for supporting three dimensional cell cultures [1]–[3]. Different approaches have been employed to evaluate the 3D scaffolds being employed for this [4]. Here we evaluate the commercial-off-the-shelf (COTS) 3D printing resins for their cytotoxicity and biochemical resistance.

a) Fabrication of the resin scaffolds for cell culture

The scaffolds were designed and generated using Openscad before being printed with commercial resins on Form 3 (Formlabs), MOAI 130 (Peopoly), Anycubic Photon, and Anycubic Photon S (Anycubic). The resins used were: Anycubic Dental castable (ADC), Anycubic Clear (AC), Formlabs Dental model V2 (FD), Formlabs Clear V4 (FC), Formlabs High Temp (FH), Tethon 3D Porcelite (TP), Tethon 3D Vitrolite (TV), Fun To Do Dentifix-3D HR (FTD), and Peopoly Professional UV (PP) resin. Fig. 2 (A) shows an example of a printed resin scaffold.

b) Cytotoxicity of the resins

Scaffolds were used as cell culture substrates for human endothelial cells (HUVECs). The scaffolds were used as such, coated with fibronectin, matrigel and collagen, most commonly used cell culture matrices. The cytotoxicity samples were taken on days 1, 2, 3, and 5 days by live (calcein AM) dye staining of cells. Fig. 1 shows the cell viability on day 7 for the resins.

Fig 1. Cytotoxicity of the resins on HUVECs cultured for 5 days

c) Biochemical compatibility test

Fig. 2. (A) 3D printed scaffold in Anycubic resin, scale bar is 500 µm (B) optical visualization of resin degradation

The printed scaffolds were incubated with commonly used molecular biology solvents: water, acetone, hexane, chloroform. Among the tested resins, only Porcelite resin from Tethon 3D was resistant to chloroform and all of the resins were resistant to water, acetone and hexane.

d) Conclusions

This work shows the cytotoxicity and biochemical resistance of

the COTS resists for the purpose of tissue engineering. A

detailed characterization of cell compatibility and biochemical

resistance is crucial for the use of resin materials in cell study.

For further development, printed resin scaffolds could be

applied for cell seeding under dynamic culture conditions such

as integrating into organ-on-chip platforms with controllable

flow, shear stress, etc. to promote vascularization for tissue

engineering constructs [5].

REFERENCES

[1] A.M. Cakmak, et al., “3D Printed Polycaprolactone/Gelatin/Bacterial Cellulose/Hydroxyapatite Composite Scaffold for Bone Tissue

Engineering,” Polymers, vol. 12, no 9, ID 1962, 2020.

[2] J.A. Crowe, et al., “Development of two-photon polymerised scaffolds for optical interrogation and neurite guidance of human iPSC-derived

cortical neuronal networks,” Lab. Chip, vol. 20, no 10, pp. 1792-1806,

2020. [3] Y. Sun, Y. You, W. Jiang, B. Wang, Q. Wu, K. Dai, “3D bioprinting

dual-factor releasing and gradient-structured constructs ready to

implant for anisotropic cartilage regeneration,” Sci. Adv., vol. 6, no 37, ID 1422, 2020.

[4] A. Palmroth, et al., “Evaluation of scaffold microstructure and

comparison of cell seeding methods using micro-computed tomography-based tools,” J. R. Soc. Interface, vol. 17, no 165, ID

20200102, 2020.

[5] H. Cui, et al., “Engineering a Novel 3D Printed Vascularized Tissue Model for Investigating Breast Cancer Metastasis to Bone,” Adv.

Healthc. Mater., vol. 9, no 15, ID 1900924, 2020.

https://www.zotero.org/google-docs/?yxPx4o

https://www.zotero.org/google-docs/?yC542c

https://www.zotero.org/google-docs/?VPFORP

https://www.zotero.org/google-docs/?qma9jG






03SAMA05-1

Numerical Simulation of Additive Manufacturing

Process of Large Parts with Polyurethane Foams

Elodie Paquet University of Nantes

Nantes, France

[email protected]

Sébastien Le Loch University of Nantes

Nantes, France

[email protected]

Benoit Furet University of Nantes

Nantes, France

[email protected]

Alain Bernard Ecole Centrale Enginnering School

of Nantes

Nantes, France

[email protected]

Sébastien Garnier, University of Nantes

Nantes, France

[email protected]

Expansive polymer-based 3D printing, also known as "FAM" technology [1], is an additive manufacturing process that makes it possible to obtain large parts by depositing successive layers of polyurethane foam [2]. This low-cost technology allows large parts to be produced in a short time. The process consists of depositing along a trajectory a polymer in a liquid state that will expand and solidify in just a few seconds to allow the printing of the new layers of material that will create the final part (Fig.1).

Fig. 1. Principle of expansive polymer-based 3D printing.

However, the quality of the parts produced with this FAM technology is strongly affected by the various thermal phenomena present during the manufacturing process and also by the geometrical gaps that are created when depositing the top layer of a bead on a layer that already has an inhomogeneous surface state due to the expansion of the material [3].

The modeling of the process implemented in the simulation chain of the FAM technology makes it possible to obtain the geometry of the deposited layer, the temperature fields in relation to the deposition speed as well as the construction of the part layer by layer, starting only from the operating parameters. (Fig.2).

Figure 2 shows the result of a simulation of three layers deposition from a robot trajectory with constant speed and programmed from the operating parameters.

Fig. 2. A simulation of three layers deposition with a FAM technology.

The objective of this work is to present our scientific approach associated with the construction of a predictive geometric and thermal model of the FAM process by the finite element method. The final objective is to choose the best 3D printing strategy to have a model with constant layers and the smallest possible shape deviation and a correct health matter.

REFERENCES

[1] Benoit Furet, Philippe Poullain, Sébastien Garnier, “3D Printing for Construction Based on a Complex Wall of Polymer-foam and Concrete”, Additive Manufacturing, vol. 28, pp. 58-64, 2019.

[2] Élodie Paquet, Benoit Furet, Sébastien Garnier, Kévin Subrin, Alain Bernard, “Additive Manufacturing of Foam for Molds and Large Components in Naval Sector,” FAST 2017 - 14th Conference on fast sea transportation & innovative materials for maritime, Sep 2017, Nantes, France.

[3] Hichem Abdessalam, Boussad Abbès, Yuming Li, Ying-Qiao Guo, Elvis Kwassi, et al., “Modelling of Polyurethane Foaming with Finite Pointset Method,” 12e Colloque national en calcul des structures, CSMA, May 2015, Giens, France.. Young, The Technical Writer’s Handbook. Mill Valley, CA: University Science, 1989.

Liquid

state Previous

solidified layer

Robot Effector

Dynamic mixer




03SAMA06-1

Additive Manufacturing of Heavy Rare Earth Free

High-coercivity Permanent Magnets

Alexey Volegov

Institute of Natural Sciences and

Mathematics

Ural Federal University

Yekaterinburg, Russia [email protected]

Nikolai Kudrevatykh


Mathematics


Yekaterinburg, Russia

[email protected]

Sergey Andreev


Mathematics


Yekaterinburg, Russia

[email protected]

Ilya Ryzhikhin


Mathematics



Ilya Okulov

Faculty of Production Engineering

University of Bremen

Bremen, Germany

[email protected]

Nadezhda Selezneva


Mathematics



Lutz Mädler

Faculty of Production Engineering

University of Bremen

Bremen, Germany [email protected]

The demand in permanent magnets has increased by about 10 - 15% annually in recent decades. This is mainly attributed to the fact that permanent magnets have become an essential part of various high-tech devices, including robots, electric motors, wind generators, levitation devices, analytical equipment, etc. The performance of these devices is determined by often a complex distribution of the magnetic field which is generated by magnetic systems. These systems are typically assembled from several principle components, including permanent magnets, magnetic conductors and magnetic flux concentrators. The latter two components typically consisting of soft magnetic materials increase weight and size of magnetic systems. Design of magnetic systems without soft magnetic components will lead to a reduced size and weight of high-tech devices as well as to a lower amount of permanent magnets required. However, synthesis of permanent magnets exhibiting complex shapes by currently available synthesis methods, e.g. sintering and machining, is economically unaffordable especially for small series products. Recently, application of additive manufacturing technologies allowed creating permanent magnets with complex shapes and, thus, demonstrated opportunities to abandon usage of soft magnetic elements in magnetic systems. There are several additive manufacturing techniques have been used to produce permanent magnets, including fused deposition modelling, stereolithography (SLA), binder jetting as well as laser powder bed fusion including selective laser melting and selective laser sintering. The weak performance, e.g., low coercivity, of the additively manufactured magnets currently hinder their application and represent the main challenge for research. Recently, we have demonstrated the opportunities to solve this problem by laser powder bed fusion and delicate design of the additive manufacturing process [1].

In this talk, feasibility of the single step laser based powder bed additive manufacturing of heavy rare earth free NdFeB magnets with technologically attractive coercivity values will be demonstrated. The additively manufactured NdFeB magnets exhibit one of the highest (up-to-date for the 3D-printed permanent magnets without addition of heavy rare earth metals) coercivity values of about 1.6 T [1]. Achieving the high value of coercivity was possible due to integration of the in-situ grain boundary (GB) infiltration into the additive manufacturing process. The NdFeB magnets were synthesized using a mixture of the hard magnetic NdFeB-based and the low-melting paramagnetic alloy powders. During the 3D-printing process, the paramagnetic alloy diffuses through the grain boundaries of the Nd2Fe14B phase and forms a paramagnetic layer between Nd2Fe14B grains. This paramagnetic layer leads to the significant reduction of the average intergrain exchange interaction between Nd2Fe14B grains. In its turn, this results in the improved coercivity values of the current additively manufactured NdFeB magnets. To understand the influence of microstructure and magnetization reversal processes on the hysteresis magnetic properties of the actual additively manufactured magnets 3D-printed magnets possessing nano- and microcrystalline microstructure were synthesized. It was found that the microcrystalline magnets demonstrate lower coercivity values as compared with that of the nanocrystalline magnets. The origin of this phenomena will be also addressed in the current talk.

REFERENCES

[1] A.S. Volegov, S.V. Andreev, N.V. Selezneva, I.A. Ryzhikhin, N.V. Kudrevatykh, L. Mädler, I.V. Okulov, “Additive manufacturing of heavy rare earth free high-coercivity permanent magnets,” Acta Mater., vol. 188, pp. 733-739, 2020.




03SAMA07-1

Electrically Conductive Adhesives as the New

Materials for Fused Filament Fabrication 3D

Printing Process

Paulina Latko-Durałek

Faculty of Materials Science and

Engineering

Warsaw University of Technology

Warsaw, Poland [email protected]

Audrey Diouf Lewis

Laboratory for Multiscale Mechanics

(LM2), Department of Mechanical

Engineering

Polytechnique Montreal

Montreal, Canada [email protected]

Daniel Therriault

Laboratory for Multiscale Mechanics

(LM2), Department of Mechanical

Engineering

Polytechnique Montreal

Montreal, Canada [email protected]

Fused Filament Fabrication (FFF) is the most commonly-

used and cost-effective way to produce 3D complex shapes from various thermoplastic polymers and their associated composites. In this work, a new type of the electrically conductive copolyamides were adapted to the FFF process. These copolyamides belong to the group of hot melt adhesives which are a mixture of different components such as polymer base, tackifier, resin, wax, additives and have the low melting point.

For this study, two types of copolyamides (EMS

Griltech, Switzerland) having different properties (Table 1)

were selected.

TABLE I. Properties of copolyamides used in the study.

Copolyamide

designation

Melt

viscosity

160C/2.16kg

[Pas]

Melt Volume

Rate

160C/2.16kg

Melting

point

[C]

coPA1 1200 9 125-135

coPA2 350 30 110-120

Both copolyamides were mixed with 7wt% of multi-

walled carbon nanotubes (MWCNTs; trade name: NC7000) using a half industrial extruder by Nanocyl, Belgium. It was found that in less viscous copolyamide (coPA2) the MWCNTs are better dispersed than in more viscous coPA2. As presented in Fig. 1, coPA2 containing 7wt% MWCNTs have much less MWCNTs agglomerates represent by black dots.

Fig. 1. Comparison of MWCNTs dispersion in coPA1 (left) and coPA2

(right). Micrographs come from a light microscope

In the next step, the nanocomposite pellets were

processed into the filaments for 3D printer using twin-screw

microextruder. These new filaments possess porosity below

1% and high flexibility without breakage during printing.

Although the addition of 7wt% MWCNTs significantly

increased the viscosity of the copolyamides, both were

printable using the nozzle of 0.6mm and the temperature of

around 70C higher than their melting point. Mechanical

properties and electrical conductivity of the filaments were

evaluated before and after 3D printing. For this, the

filaments were printed using Raise3D Pro2D on 5 different

temperatures: 205C, 215C, 225C, 235C and 245C. It

was found that electrical conductivity is improved with an

increase of the nozzle temperature while the tensile strength

decreases. Using these thermoplastic adhesives it was

possible to print the conductive tracks onto the polymeric

fabrics by FFF 3D printing which maintain the conductive

properties even during bending. Fig.2 presents the printed

nanocomposite onto the polymeric fabric.

Fig. 2. Polymeric fabric with printed conductive adhesive (coPA1+7wt% MWCNTs) on the surface

This project was conducted by the support of the Polish

National Agency for Academic Exchange (NAWA) in

funding under the Bekker programme received by Dr.

Paulina Latko-Durałek.




03SAMA08-1

4D Printing: Functional and Microstructure

Engineering in Powder Bed Additive Manufacturing

Andrey Koptyug

Sports Tech Research Center

Mid Sweden University

Östersund, Sweden [email protected]

Lars-Erik Rännar




Carlos Botero




Stefan Roos



Östersund, Sweden

[email protected]

William Sjöström




Mikael Bäckström



Östersund, Sweden

[email protected]

Additive manufacturing (AM) family of technologies is often referred to as 3D printing. It is a rapidly maturing technology area mostly known for its unprecedented freedom of the possible component shapes. But research and development efforts are steadily highlighting other benefits of AM, introducing new materials with unique properties not available with other manufacturing processes, and new modalities, in particular providing capacity to manufacture such materials, and for steering of the material properties within the components. Functionalization of the material properties in AM already can be achieved using same precursor material within a single manufacturing process effectively adding 4

th dimension to 3D printing. Different

authors suggest expansions of 3D technology toward quite different “4

th dimension” (e.g. “time”, with additive

manufacturing of time-responsive products [1]). In present context we limit the discussion to the extra dimension of “material properties”.

Development of new enabling modalities for AM is already attracting wide attention, which is quite prominent for example with laser and electron beam based powder-bed fusion (PBF) AM technologies [2, 3]. One of the key properties of modern PBF-AM machines is their ability to vary the beam energy and beam application strategies within each processed material layer and its sub-sections. It allows manipulating molten pool solidification rate with high degree of localization, and varying the thermal history of the component sections. It is confirmed that with pre-alloyed precursor powder in PBF-AM it is possible to manipulate material microstructure and thus material properties in three dimensions [4, 5]. AM systems with high beam energy are already efficiently used for in-situ alloying of powder blends, aiming at producing homogeneous alloyed materials from cheaper precursors, or at preserving non-equilibrium phases in the resulting material. But manipulating beam energy deposition rates and beam scanning strategies in AM of powder blends also allows to produce functionally graded materials with local metal-metal composite and fully alloyed sections [5, 6].

It is already clear that beam energy deposition rate manipulation provides a way to manufacture components with high degree of functionalization at high spatial resolution, as specific microstructure is commonly responsible for many different properties (mechanical, magnetic etc.). And thus one can say that such manipulations performed during the additive manufacturing add 4

th

dimension (“material properties”) to three-dimensional shape of components, resulting in true 4D printing.

Present talk provides an overview of already available and suggested new modalities allowing for the material property manipulation in 3D, and of the challenges on the way towards their wide industrial applications. Corresponding illustrations on the possibilities opened by these new modalities will be using the examples from electron beam melting of different materials. A discussion will be also devoted to the pre-alloyed and blended- powder precursors.

REFERENCES

[1] M. Quanjin, M. Rejab, M. Idris, N. Kumar, M. Abdullah, G. Reddy, “Recent 3D and 4D Intelligent Printing Technologies: A Comparative Review and Future Perspective,” Proc. Comput. Sci., vol. 167, pp. 1210-1219, 2020.

[2] B. Attard, S. Cruchley, Ch. Beetz, M. Megahed, Y. Chiu, M. Attallah, “Microstructural Control During Laser Powder Fusion to Create Graded Microstructure Ni-superalloy Components,” Additive Manufacturing, vol. 36, ID 10432, 2020.

[3] A. Koptyug, M. Bäckström, C. Botero, V. Popov, E. Chudinova, “Developing New Materials for Electron Beam Melting: Experiences and Challenges,” Mater. Sci. Forum, vol. 941, pp. 290-295, 2018.

[4] R. Laptev, N. Pushilina, E. Kashkarov, M. Syrtanov, E. Stepanova, A. Koptyug, A. Lider, “Influence of Beam Current on Microstructure of Electron Beam Melted Ti-6Al4V Alloy,” Prog. Nat. Sci.: Mater. Int., vol. 29, pp. 440-446, 2019.

[5] A. Koptyug, L.-E. Rännar, C. Botero, M. Bäckström and V. Popov, “Unique Material Compositions Obtained By Electron Beam Melting Of Blended Powders," EPMA EuroPM 2018, ep18-3989398, Proceedings of Euro PM2018 Congress & Exhibition, Bilbao, 14-18 October 2018.

[6] A. Koptyug, V. Popov Jr., C. Botero Vega, E. Jiménez-Piqué, A. Katz-Demyanetz, L.-E. Rännar, M. Bäckström, “Compositionally-tailored Steel-based Materials Manufactured by Electron Beam Melting Using Blended Pre-alloyed Powders,” Mater. Sci. Eng. A, vol. 771, ID 138587, 2020.

Scientific Edition

2020 IEEE 10th

International Conference on

“Nanomaterials: Applications & Properties”

(NAP-2020)

ABSTRACTS

A Virtual Conference

November 9 – 13, 2020

General Chairs of the NAP-2020 Conference Alexander Pogrebnjak

Valentine Novosad

Secretary of the Conference Yurii Shabelnyk

Computer design Yurii Shabelnyk

Сумський державний університет, 40007, м. Суми, вул. Р.-Корсакова, 2

Свідоцтво про внесення суб’єкта видавничої справи до Державного реєстру

ДК № 3062 від 17.12.2007.

Надруковано у друкарні СумДУ

40007, м. Суми, вул. Р.-Корсакова, 2.

Documents

ORGANIZING COMMITTEE - nap.sumdu.edu.ua