The oxygen octahedral distortion induced magnetic enhancement in multiferroic Bi1−xYbxFe0.95Co0.05O3 powders

The Bi1−xYbxFe0.95Co0.05O3 (x range from 0 to 0.25) powders have been prepared by the sol-gel method. A phase transition from rhombohedral R3c to orthorhombic Pbnm via a biphasic region has been observed. The Rietveld refinement and Raman scattering analyses suggest an increase of the rotation of the oxygen octahedra ω for x ⩽ 0.05. The remanent magnetization of Bi1−xYbxFe0.95Co0.05O3 is enhanced substantially at the R3c phase region. The enhancement of the magnetization is attributed to the augment of the Dzyaloshinsky-Moriya interaction and suppression of the spin cycloid, which is determined by ω.