Abstract: We have investigated the saturation magnetization and structure of MFe2O4 (M = Co, Ni and Mn) films prepared by annealing process of MO (1 nm) / Fe2O3 (1 nm) multilayers. The highest saturation magnetization Ms of 330 G and spinel structure are obtained in insulating CoFe2O4 films after annealing at 773 K. In the case of our semi-conducting NiFe2O4 films, the highest saturation magnetization Ms of 167 G and iron segregated spinel structure are observed after annealing at 823 K. The highest saturation magnetization Ms of 198 G and spinel structure are found in MnFe2O4 films after annealing at 873 K. The spinel MFe2O4 films obtained by annealing are become the promising candidate materials for the research area of spintronics.

Keywords: annealing, spin polarization, saturation magnetization, spinel structure, half-metal and spin filter.