Critical current in Ag/BPSCCO tapes using low purity materials |
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Authors: | S R Shukla Y S Reddy R G Sharma |
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Institution: | (1) National Physical Laboratory, 110 012 New Delhi, India |
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Abstract: | Silver-clad Bi1·7Pb0·4Sr1·8Ca2Cu3·5O
x
(BPSCCO) tapes have been fabricated using low purity (98–99%) starting materials and following the powder-in-tube technique.
MaximumJ
c
values of 6·14 × 103 A·cm−2 at 77 K and 1·4 × 105 A·cm−2 at 4·2 K have been obtained in tapes subjected to the process of intermediate rolling and sintering. The bulk superconducting
material used for the tape-fabrication contains both 2223 and 2212 phases in the ratio 60:40. A pure phase material and the
optimization of the sintering parameters are expected to yield much higherJ
c
values at 77 K. It is possible that the copper-rich phase(s) and/or a small amount of iron impurity (60 ppm) present in CuO
might be acting as flux pinning sites and could be responsible for highJ
c
values. |
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Keywords: | Critical current density tapes BPSCCO system sintering flux pinning powder-in-tube technique |
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