Formation of ferrite thin films by vacuum evaporation with annealing process

Cobalt ferrite thin films were prepared in successive processes by vacuum evaporation of cobalt on hematite (αFe2O3) films and annealing at relatively low temperature. The surfaces of these films were observed by transmission electron micrograph(TEM) and scanning electron micrograph(SEM), also their structures were identified using transmission electron diffraction(TED) and reflection electron diffraction(RED) methods. Then, a diffusion profile of depth distribution of cobalt ions into (αFe2O3) layer was investigated by Auger electron spectroscopy(AES) analysis. Magnetic properties were measured with a vibrating sample magnetometer. Results showed that cobalt ions migrated easily into a (αFe2O3) layer at relatively low temperature and formed ferrite thin films in the form of CoxFe3-xO4. Their magnetic properties, such as high coercive force, large residual magnetization and smooth surface, indicate considerable possibilities to obtain excellent magnetic medium for high density recording disk.