Accelerated formation of 110 K high T c phase in the Ca- and Cu-rich Bi-Pb-Sr-Ca-Cu-O system

The crystal structure and superconducting properties of the Bi-Pb-Sr-Ca-Cu-O system with Ca- and Cu-rich nominal composition were investigated. A nearly single-phased 110 K high Tc superconductor can be obtained with 852 °C/20 h sintering from the starting composition of Bi1.7Pb0.4Sr1.6Ca2.4Cu3.6Oy. X-ray diffraction patterns, resistivity measurement, diamagnetic susceptibility results, and scanning electron micrographs all indicate that the Ca- and Cu-rich nominal composition would result in better superconducting properties than those of Ca:Sr=1:1 Bi-Pb-Sr-Ca-Cu-O compounds in a much shorter sintering time.