Combination of Ag Substrate Decoration with Introduction of BaZrO3 Nano-Inclusions for Enhancing Critical Current

Density of YBa2Cu3O7 Films

Nano-engineered pinning centres

Nano-dotstarget YBCO +BZO

target

LASER

STO substrate

YBCO

Ag

BZO nanorods

AFM image of Ag nano-dots on STO substrate deposited at temperature of 450 oC in vacuum with 15 laser pulses.

Formation of BZO nanorods in YBCO matrix

V.S. Dang a, P. Mikheenko a, A. Sarkar a, M.M. Awang Kechick a, J.S. Abell a, P. Paturic, H. Huhtinenc A. Crisan a,b,*

a School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT , United Kingdomb National Institute of Materials Physics, Bucharest 077125, Romania

cWihuri Physical Laboratory, Department of Physics and Astronomy, FI-20014, University of Turku, Finland

TEM image of a substrate-decorated sample (with 15 laser pulses) taken near the film/substrate interface. The high resolution image on the left a) shows local disorder of the YBCO matrix probably caused by Ag nano-dot. The lower resolution image on the right b) shows BZO nanorods

structure formed in YBCO film.

TEM images Conclusions and Acknowledgements

The financial support of the European Commission through the Marie Curie Excellence Grant MEXT-CT-2006-041111 “NanoTechPinningHTS”, the ESF-NES Network, and the Romanian Ministry of Education and Research, is gratefully acknowledged.

10 100

1

10

4 T

2 T

1 T

H = 0

J c(MA

/cm

2 )

Number of pulses on Ag target

T = 65 K

Critical current density of Ag substrate-decorated YBCO + 4%BZO films grown with different number of laser pulses on Ag target at different applied fields as marked in the plot

Thickness dependence of the critical current density for the films grown on substrates

decorated with 15 pulses on Ag, at different applied magnetic fields from 0 to 2 T.

Thickness dependence of critical temperature of YBCO + 4%BZO films with (red circles) and

without Ag (black squares). The substrate decoration increases Tc of the films.

SEM images of YBCO + 4%BZO films grown on substrates decorated with 15 pulses on Ag, with different thickness: a) 2.4 mm, b) 1.8 mm, c) 1.2 mm and d) 0.4 mm. The scale as shown in a) is the same for all images.

0 1 2 3 40

1

2

3

J c(MA

/cm

2 )

Thickness (m)

0T 1T 2T 0 T without Ag 1T 2T

77.3K

with 15 pulses Ag

0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.288.4

88.8

89.2

89.6

90.0

90.4

90.8

Tc

Film thickness (m)

without Ag with 15 pulses Ag decoration

SP-090

AFM images of Ag nanodots, deposited at 450o C in Vacuum, on STO substrates obtained with different number of laser pulses: a) 5, b) 15, c) 30 and d) 45. The scale as shown in a) is the same for all images.

Optimisation of Ag nanodots, critical current density and critical temperature

Ag substrate decoration is quite effective in increasing Jc in BZO doped YBCO thick and thin films

The optimum number of pulses on Ag is between 15 and 30

By Ag substrate decoration, Tc is also increased to a value close to Tc of pure YBCO, up to 90.6 K

Both BZO nanorods and nanoparticles are also found in TEM images of the films.