Abstract
La-Co-doped ferrite is widely used due to its excellent magnetic properties, but the mechanisms of La-Co doping on its phase formation and magnetic properties remain unclear. This study clarifies the phase formation mechanisms and reveals that La-Co doping reduces the formation temperatures of the intermediate phase SrFeO(3-x) and thus the final SrFe(12)O(19) phase. This promotes complete formation of SrFe(12)O(19), enhancing saturation magnetization. The unexpected change in coercivity after La-Co doping contradicts the variation in the determined magnetocrystalline anisotropy field. We identify that it arises from the La-Co doping lowering the formation temperature of SrFe(12)O(19), leading to excessive particle growth.