Effect of (Bi,Pb)2 Sr2CuO6 phase on critical current density of Ag/(Bi,Pb)2Sr2Ca2Cu3O10 tapes

Abstract

The phase evolution, critical current density (Jc) and irreversibility field (Hirr) for (Bi,Pb)2Sr2Ca2Cu3O10 (2223) tapes have been studied through a two-step sintering process. The tapes sintered at 840°C without second-step annealing at 820°C contain a small fraction of (Bi,Pb)2Sr2CuO6 (2201). 2201 phase vanishes when the tapes are annealed at 820°C for 30 h after sintering at 840°C. (Bi,Pb)2Sr2CuO6 (2201) phase was found to be the predominant factor for the depression of Jc of the tapes. The Jc vs. magnetic field shows that the depression of Jc occurs only in the low field region, indicating that 2201 phase act as weak links in the tapes. © 1997 Elsevier Science B. V.