Phase Equilibrium ofthe La-Ca-Mn-O System

摘要

Phase equilibriu mof the La-Ca-Mn-O system at 900degC in atmosphere was examined and illustratedin the form of a phase diagram.La_(1-x)Ca_xMnO_3 forms a solid solution with two distinct perovskite structures (R3c and Pnma).A new compund La_2Ca_2MnO_7,identified in the phas diagram,crystallizes in a rhombohedral structure (R3) withthelattice constants of a=5.62176(4),c=17.3161(2)A.The phase regins in the La-Ca-Mn-O system were clarified based on the X-ray diffraction analysis of the samples.