Reproducible Processing for High-Tc Superconducting Tl-Ba-Ca-Cu-O-Phases

Abstract
In order to establish the reproducible processing for high-T c superconducting Tl-Ba-Ca-Cu-O phases, three kinds of superconductive samples with different starting compositions of Tl:Ba:Ca:Cu=2:2:2:3, 2.5:2:2:3 and 3:2:2:3 were heat treated under various conditions. The optimum starting composition was found to be 2:2:2:3. A particular heat treatment of the 2:2:2:3 sample elicited polycrystalline materials showing a zero-resistance temperature at 120.3 K and an onset temperature of the diamagnetic shift at 127 K.