High-Tc Superconducting Glass Ceramics Based on the Bi-Ca-Sr-Cu-O System

Abstract
Various superconducting glass ceramics based on the Bi-Ca-Sr-Cu-O system with T c(onset)=80∼95 K and T c(zero)=63∼78 K were prepared by a melt-quenching method. The melt-quenched samples of Bi1.5CaSrCu2O x and Bi1.5Ca1.5SrCu2O x were found to be a glass with a glass transition of about 425°C; these samples became high-T c superconductors by annealing at 820°C.