MAGNETIC-PROPERTIES OF (COFE2O4)-(CO-COO) COMPOSITE FILMS FOR PERPENDICULAR MAGNETIC RECORDING

Cobalt ferrite films were prepared by facing targets sputtering, and t hen post-annealed at various temperatures (Ta=200-500 degrees C) in ai r. Their magnetic properties and line structure were investigated A co ercivity (Hc(perpendicular to)) measured in a perpendicular direction to the film surface of a film deposited at the oxygen gas pressure (Po 2) of 0 m Torr and post-annealed at 300 degrees C was 1.5 kOe. The val ue was 3.5 times greater than a coercivity (Hc parallel to) measured i n a parallel direction to the film surface. This high coercivity ratio (Hc(perpendicular to)/Hc parallel to) showed that this film had the p erpendicular magnetic anisotropy. It was investigated by the SEM obser vation that the perpendicular magnetic anisotropy was mainly caused by the columnar structure of the film, Moreover, the film was found to b e made up of a (CoFe2O4)-(Co-CoO) composite by the XPS measurement of the binding energies of Co2p and Fe2p electrons of the film.