Cation distribution and intrinsic magnetic properties of Co-Ti-doped <i>M</i>-type barium ferrite

Abstract

The structural and magnetic properties of BaFe12−2xCoxTixO19 (0≤x≤1.0) M-type barium ferrite have been investigated by means of neutron powder diffraction and high-field magnetization measurements. The cationic distribution and magnetic moments of the five different metallic sublattices are determined and compared to the experimental saturation magnetization. It is found that about 50% of Co ions occupy tetrahedral sites, thus being ineffective in the reduction of the uniaxial magnetic anisotropy, while Ti ions prefer the 4fVI octahedral sites. All in all, a clear hierarchy of sublattice preferences is defined. Although the collinearity of the magnetic structure is progressively broken, mainly above x≊0.7, the overall behavior remains ferrimagnetic. The strong local spin canting is tentatively attributed to the localization of diamagnetic Ti ions in the 4fVI octahedral sites.