STRUCTURE DETERMINATION OF FERROMAGNETIC PEROVSKITE BiMnO3

摘要

Structure of ferromagnetic BiMnO3 synthesized at high pressure has been determined by electron diffraction and neutron powder diffraction. This structure is related to a heavily distorted perovskite structure, having monoclinic symmetry, space group C2, with a=9.5323(6) angstroms, b=5.6064(3) angstroms, c=9.8535(7) angstroms, and beta=110.667(5) degrees. The distortion is caused by a polarized Bi 6s2 lone pair. Every trivalent Mn cation reveals the Jahn-Teller distortion and ordering of a vacant dx2-y2 orbital is important for ferromagnetism. 11 refs.