Abstract
It has been reported that outgoing gas from a substrate affects the magnetic properties of Co-Cr film during deposition of Co-Cr on the substrate.
Therefore, the procedure of degassing a substrate by heating it in a vacuum prior to formation of Co-Cr film is necessary to reduce the amount of outgoing gas if high perpendicular magnetic anisotropy of the Co-Cr film is to be obtained for perpendicular magnetic recording media.
Three kinds of polymer substrate were used to study the influence of the degassing procedure on the properties of Co-Cr film deposited on each polymer substrate by changing sputtering Ar pressure. With polyimide film which has high water absorption and high glass transition temperature, the degassing at 100 °C in a vacuum is not sufficient to increase magnetic anisotropy of Co-Cr film. The large amount of outgoing gas from a substrate such as polyimide disturbs the crystal orientation of Co-Cr and reduces the magnetic anisotropy of Co-Cr film. But a comparatively small amount of outgoing gas from a substrate such as PET film prevents Cr atoms from segregating at the columnar boundary and reduces coercive force in the perpendicular direction.
