On the Formation of High-T_C phase in the Bi-based Supercinducting Glass-Ceramics

Abstract

We prepared superconducting Bi_1.6Pb_0.4-xTe_xSr2Ca₂Cu₃O_y ( x=0.1, 0.2, 0.3 and 0.4 ) glass-ceramics by the melt-quenching method and examined the effect of Te addition on the formation of high-T_c phase. It was found that the formation of the high-T_c phase was largely enhanced by the addition of a small amount (x=0.1 and 0.2 ) of Te element. In the Bi_1.6Te_0.4Sr₂Ca₂Cu₃O_y glass-ceramics, the main superconducting phase was the low-T_c phase. It was concluded that the lowering of the partial melting temperature at around 870°C caused by the coexistence of Pb and Te elements was very important for the formation of the high-T_c phase. The critical temperature of the sample ( x=0.2 ) annealed at 850°C for 100h was 103K.