The Subsolidus Phase Diagram of the LaO_1.5-BaO-CuO System at 1000°C in Air

Abstract

Phase equilibrium in the LaO_1.5-BaO-CuO system at 1000°C in air has been studied mainly by powder X-ray diffraction. La_2-xBa_xCuO_δ coexists with CuO, La₄BaCu₅O_δ, La₃Ba₃Cu₆O_δ and La_2-yBa_1+yCu₂O_δ (y=0.3) for 0≤x<0.05, 0.05<x<0.15, 0.15<x<0.23 and 0.23<x≤0.3, respectively. An anomalous sintering phenomenon was observed for a composition of x=0.125 of La_2-xBa_xCuO_δ. We have newly found that the Ba-rich compositions of 0.125<x<0.3 were mixtures of two phases with x=0.125 and x=0.3 below 950°C.