Dependence of Critical Current Density on Tape Thickness in Ag-Sheathed Bi2223 and Bi2212 Tapes

Abstract

Critical current density Jc, morphology and microstructure are studied on the Ag-sheathed (Bi,Pb)2Sr2Ca2Cu3Ox(Bi2223) and Bi2Sr2CaCu2Ox (Bi2212) tapes with thickness d between 0.05 ram ana 1.0 mm. Some similalities appear in thickness dependence of Jc at 77 K between both cases. The Jc value increases gradually with a decrease in d from 1.0 to 0.2 mm by co-deformation between Ag sheath and ceramics, and it rises sharply in thinner tapes of d<0.2 mm by densification of ceramics core. A peak of Jc=15,300 A/cm2 for Bi2223 and 5,300 A/cm2 for Bi2212 appears when d=0.10 mm, which is caused by the distortion of Ag/ ceramics interface for the former and by a leakage of ceramics from the tape for the latter.