NSF NanoSystems Engineering Research Center
Translational Applications of Nanoscale Multiferroic Systems (TANMS)
Fabrication and Characterization of Magneto-Refractive Glass Pranathi M Rao, A. Garcia, S. Strutner, G. Carman Department of Mechanical and Aerospace Engineering, University of California, Los Angeles
University of California, Los Angeles
University of California, Berkeley
Cornell University
California State University, Northridge
Swiss Federal Institute of Technology, ETH Zurich
Abstract
Motivation
Fabrication Process
Utilization of a magneto-refractive glass in optical fibers will
result in magnetic field sensors. A magneto-refractive material’s
index of refraction shifts when in the presence of a magnetic
field. Literature shows La0.65Sr0.35MnO3 has magneto-refractive
qualities. The fabrication of the magneto-refractive glass
involved sol-gel chemistry, a process used to create a suspension
of nanocomposite particles of LSMO cores and SiO2 shells. A
glass slide was dip-coated into the suspension and then baked at
500℃. These slides were used to test the material. Changes had
to be made to the original sample recipe due to the lack of
desired results. Improvements included O2 plasma treatment
before dip-coating and spin-coating the glass substrates. Recipes
concerning the core-shell particle size were found but were not
tested. Monodispersity of nanocomposite particle size would
allow a more uniform distribution on the glass substrate. The
uniformity in distribution will increase the accuracy of the data
collected during characterization.
To fabricate and characterize a magneto-
refractive glass.
Sol-Gel chemistry: a process resulting
in nanocomposite core-shell particles.
• Magneto-refractive materials see a
shift in the index of refraction when
in the presence of a magnetic field.
• Index of refraction is the ratio
between the speed of light in a
vacuum and the speed of light in the
a given material
• The index of refraction is used to
characterize the bending and
reflection of light.
Improvements • Ingredient Change: Cyclohexane and Igepal
- Cyclohexane takes the role of the solvent and Igepal acts as the
surfactant. These chemicals are used instead of Isopropanol and soap.1
• Dip-Coating: Improved surface wetting characteristic
- Putting the glass substrate in an O2 plasma will cause the water to
have a stronger attraction to the glass and thus lead to better
dipcoating results.
• Spin-Coating: Better distribution of particles on surface
• SEM imaging: Capable of measuring size of core shell particles
- If the silicon wafer was pretreated with a solution of KOH, water, and
ethanol then the imaging will be of a higher quality.
• Stober process: Creating Monodispersity
- Creating a relationship between the concentrations of ingredients
- [TEOS] = 0.22 – 1.24M ; [NH3] = 0.81[TEOS]; [H20] = 6.25[TEOS]2
Characterization Setup
• The characterization of the material involves a laser to shoot an incident ray at a certain angle onto the
material with the unknown index of refraction and a photo diode to measure the intensity of the reflected ray.
• The test is conducted with and without the presence of a magnetic field and a shift in the reflectivity would
then indicate a shift in the index of refraction thus confirming the magneto-refractive properties of LSMO.
Future Steps The fabrication process needs to result in relative monodispersity in the solutions. The characterization of
the material will depend on the uniform distribution of LSMO particles on the glass substrate
This work was supported by the National Science Foundation through the Cooperative Agreement Award EEC-1160504 for Solicitation NSF 11-537 (TANMS) managed by Dr. Deborah J. Jackson and supported by
the Aero Institute. Special thanks to Laura Schellas, Wei Yang Sun, Kyle Wetzlar.
Acknowledgements
Objective
Background
Magneto-refractive glass can be used in an
optical fiber as a magnetic field sensor
Solvent NH3 TEOS LSMO Surfactant H2O
Goal: LSMO core/SiO2 shell
Snell’s Law Fresnel’s Equation
Bending (Refracted Ray) Reflected Intensity
References
Dipcoat a glass substrate
into solution.
Bake the glass slides at
500℃ in order to dry out
alcohol and water
1. Li, T.; Moon, J.; Morrone, A.A.; Mecholsky J.J.; Talham D.R.; Adair J. H. Langmuir, 15, (1999), 4328-4334. 2. 2. Wang, X.; Shen Z. ; Sang, T.; Cheng X.; Li, M.; Chen, L.; Wang Z. Journal of Colloid and Interface Science, 341, (2010), 23-29. 3. Celzard, A.; Mareche, J.F. Journal of Chemcial Education (2002) 79. 4. Yasumori, A.; Matsumoto, H.; Hayashi, S,; Okada, K. Journal of Sol-Gel Science and Technology, 18, (2000), 249-258.
Fabrication Results
),( nRR
Spin coating
Original Dipcoating Methods Glass slides undergone O2 plasma
Dipcoated
3.81 cm 3.81 cm
10X 0.5mm 0.5mm 10X
0.5mm 10X
1.27 cm
Optical Image Optical Image
Optical Image SEM Image By Wei Yang sun and Kyle Wetzlar
Fabrication Analysis
• O2 plasma treatment resulted in better distribution and adhesion of the core-shell particles onto the glass slides. • Spincoating resulted in a thicker coating but the SEM images showed an undesirable morphology of the particles.
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