Sol-gel processing of high-Tc superconductors in the Bi–(Pb)–Sr–Ca–Cu–O system

Abstract

Superconducting materials in the Bi–(Pb)–Sr–Ca–Cu–O system have been synthesized by sol-gel processing from nitrates by complexation with citric acid. The gelation process and the microstructures of the gels obtained have been studied through titration and SEM observation. Their phase transformations and microstructure development, during heat treatment, have also been investigated. The critical temperature Tc of superconductors by this sol-gel processing can reach above 100 K.