High-temperature XRD and DTA studies of BiMnO3 perovskite

BiMnO3 synthesized at high pressure is a triclinically distorted perovskite and a ferromagnetic with T-c = 108 K. High-temperature X-ray diffraction a nalysis, thermal analysis, thermogravimetry, and magnetic measurements were used to determine stability and the melting sequence of BiMnO3 phase in ai r. Structural phase transition from triclinic to tetragonal structure has b een determined at 490 degrees C in air for a polycrystalline BiMnO3 perovsk ite. Two phases form immediately at the decomposition temperature of 600 de grees C, namely Bi2O3 and Bi2O3. 2Mn(2)O(3+delta). The Bi2O3. 2Mn(2)O(3+del ta) coexists with liquid up to at least 900 degrees C. (C) 1999 Academic Pr ess.