Perpendicular Magnetic Anisotropy of CoOx Films Prepared by Targets Facing Type of Sputtering

CoO
_x
thin films with perpendicular magnetic anisotropy (PMA) were prepared at room temperature by the reactive facing-target sputtering technique. We investigated the PMA, coercivity and static magnetization process of the film samples, with the following results. (1) CoO
_x
films with a columnar structure are composed of hep Co and fcc CoO. (2) The highest perpendicular anisotropy energy K
_u
was 2.3×10
⁶
erg/cm
³
. K
_u
increases with increasing M
_s
; the PMA of CoO
_x
thin films is attributed to the magnetocrystalline anisotropy of Co. (3) Hca increases with decreasing diameter of columnar grains in CoO
_x
thin films. (4) The dependence of H
_c⊥
on the direction of the applied magnetic field is similar to that expected from the Stoner-Wohlfarth model. The static magnetization process in CoO
_x
thin films is mainly the rotational type.