Superconductivity of Bi₂Sr₂Ca₂Cu₃Pb_xO_y (x=0.2, 0.4, 0.6)

Abstract

The addition of Pb to the superconducting Bi-Sr-Ca-Cu-O system is found to increase the volume fraction of the high- T c phase ( T c >100 K) determined by the ac susceptibility and the X-ray powder diffraction pattern. It also lowers the optimum firing temperature to produce the high- T c phase. The peaks attributed to the high- T c phase in the X-ray diffraction pattern become sharper, which indicates that the addition of Pb promotes crystallization. It is found by differential thermal analyses that Pb also acts as a flux.