Effect of Processing on the Structure, Oxygen Content, and Superconductivity of LaBa₂Cu₃O_y

Abstract

We have examined the structure, oxygen content, and superconductivity of a LaBa 2 Cu 3 O y superconductor heat treated at different temperatures and in different atmospheres. It was found that the expansion of the c-axis, which was caused by the removal of oxygen, might be the reason for the ordering of barium and lanthanum ions when the specimen is heated in a reducing atmosphere. The anomaly in the expansion of the c-axis was also observed when oxygen was removed. Mechanisms of the orthorhombictetragonal transition and the occurrence of the anomaly in the c-axis have been proposed.