Superconductive Transition at 120 K in a Tl-Bi-Sr-Ca-Cu-O System

Abstract
Superconductivity and crystal structure of a Tl-Bi-Sr-Ca-Cu-O system were studied. A T c-onset temperature of 120 K as determined by AC susceptibility measurement was achieved for the nominal composition of Tl2Bi0.5Sr2Ca3Cu4O x ceramics sintered at 900°C for 100 h. The superconductive phases synthesized in the Tl-Bi-Sr-Ca-Cu-O system were (Tl, Bi)Sr2CaCu2O x and (Tl, Bi)Sr2Ca2Cu3O x (“1212” and “1223” phases). Superconductivity at 120 K may be due to this “1223” phase.