Further studies on Ag/BPSCCO tapes using low purity materials |
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Authors: | S R Shukla Y S Reddy N Kumar S K Sharma R G Sharma |
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Institution: | (1) National Physical Laboratory, 110 012 New Delhi, India |
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Abstract: | Transmission electron microscopic (TEM) studies are reported on Ag-clad Bi1.7 Pb0.4Sr1.8Ca2Cu3.5O
x
tapes prepared by using low purity (98–99%) commercial grade materials. The self-fieldJ
c values of these tapes viz. 6.14 × 103 A.cm−2 at 77 K and 1.4 × 105 A.cm−2 at 4.2 K, reported in an earlier publication, were significantly higher than the correspondingJ
c values in tapes prepared with high purity (99.99%) materials. The TEM pictures on the low purity core material of the tapes
reveal the presence of stacking faults and the intergrowth of the 2212 and 2223 phases which could be acting as flux pinning
sites and responsible for enhancedJ
c values. These defects can perhaps be traced back to the presence of 60 ppm iron in the low purity CuO as revealed by atomic
absorption analysis reported earlier. |
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Keywords: | Critical current density Ag-clad BPSCCO tapes structural inhomogeneities |
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