Magnetic properties and crystalline structure of BiFe_1-xT_xO₃(T=Co and Ni)

The doping content dependence of crystalline structures, saturation magnetization and coercivities of BiFe_1-xCoxO₃ was compared with that of BiFe_1-xNi_xO₃. All the samples are fabricated by solid-state sintering. It is found that ferromagnetic cubic structure in doping samples is the main source of magnetic properties. The Curie temperatures of Ni-doped samples are higher than those of Co-doped samples. The difference in Curie temperature might be due to the variation of magnetic super-exchange coupling between magnetic cations which is caused by interatomie distance and the kinds of cations. Ni-doped samples have smaller eoereivities than Codoped samples. The large coercivity results from the lattice distortion and the strong single ion anisotropy of Co cations. The results of hysteresis loops of BiCoO₃ at different temperatures show that the magnetocrystalline anisotropy of BiCoO₃ samples increases with decreasing temperature.