Abstract
The Ba-ferrite particles have a positive temperature coefficient of dH_c/dT. From the viewpoint of recording system applications, the dH_c/dT should be reduced in order to improve the operating margin for temperature change. In the Ba-ferrite there are five distinct crystallographic sites or sublattices, and the Fe^<3+> ion located on different site has different contribution to crystalline anisotropy. The replace of Fe^<3+> ions by Zn^<2+> Ni^<2+> and Ti^<4+> ion will effect on the above-mentioned properties of ferrite. The Zn-Ti, Ni-Ti, and Ni-Zn-Ti substituted Ba-ferrite particles were investigated. It was found that the Zn-Ti substituted Ba-ferrite particles have higher σ_s, but large temperature coefficient of coercivity dH_c/dT. In the case of Ni-Ti and Ni-Zn-Ti substitution the dH_c/dT could be reduced to small value, near to zero or negative value, while the σ_s decreases very slowly with increasing the amount of substitutution.
