Thallium cuprate 1223 type.: I. Its elaboration and dependence of chemical and thermal stability and of superconducting transition temperature on Tl/Pb and Sr/Ba substitutions

Abstract The formation of samples with nominal composition (Tl x Pb 1− x )(Sr 1− y Ba y ) 2 Ca 2 Cu 3 O z was followed by X-ray diffraction study. With the chosen elaboration conditions, the 1223 phases were formed in two steps with a 1212 type phase observed as an intermediate compound. From the results, the limits of the 1223 single phase field were determined for temperature below 930°C and under 1 bar of oxygen. Samples with 91% purity were obtained and for compositions located outside the limits of the monophased field, a Tl/Pb–Sr/Ba-1212 and a substituted Tl/Pb and Sr/Ba perovskite were found as the main impurities.