Neutron powder diffraction study on the crystal and magnetic structures of BiCrO3

作者：Belik Alexei A^*; Iikubo Satoshi; Kodama Katsuaki; Igawa Naoki; Shamoto Shinichi; Takayama Muromachi Eiji

来源：Chemistry of Materials, 2008, 20(11): 3765-3769.

DOI：10.1021/cm800375d

crystal and magnetic structures of polycrystalline BiCrO3 were determined by the Rietveld method from neutron diffraction data measured at temperatures from 7 to 490 K. BiCrO3 crystallizes in the orthorhombic system above 420 K (space group Pnma; Z = 4; a = 5.54568(12) angstrom, b = 7.7577(2) angstrom, and c = 5.42862(12) angstrom at 490 K) in the GdFeO3-type structure. Below 420 K down to 7 K, a monoclinic structure is stable with C2/c symmetry (a = 9.4641(4) angstrom, b = 5.4790(2) angstrom, c = 9.5850(4) angstrom, and P = 108.568(3)degrees at 7 K). A possible model for antiferromagnetic order below T-N = 109 K is proposed with a propagation vector of k = (0, 0, 0). In this model, magnetic moments of Cr3+ ions are coupled antiferromagnetically in all directions, forming a G-type antiferromagnetic structure. Refined magnetic moments at 7, 50, and 80 K are 2.55(2)mu(B), 2.43(2)mu(B), and 2.09(2)mu(B), respectively. The structure refinements revealed no deviation from stoichiometry in BiCrO3.

• 出版日期2008-6-10