VERTICAL RECORDING MEDIUM

摘要

PURPOSE:To obtain a vertically magnetized film of high performance which has excellent durability and weatherability, decreases the wear loss of a head and is less deteriorated in magnetic characteristics by a protective film by forming a thin Co-Cr oxide film in a hybridized fine crystal and amorphous state on a thin Co-Cr alloy film having vertical anisotropy. CONSTITUTION:The Co-Cr oxide film contg. 15-65% Cr by weight is formed in a hybridized fine crystal and amorphous state to >=100 and <=300Angstrom thickness on the thin Co-Cr alloy film which contains 16-23% Cr by weight and is formed on a nonmagnetic substrate consisting of PET, etc. so as to have the vertical anisotropy. The hybridized fine crystal and amorphous state is formed by sputtering Co-Cr as a target and depositing the oxide film of Co-Cr on the thin Co-Cr film under the oxygen partial pressure at the point where the saturation magnetization Ms is zero when the oxygen partial pressure is increased from zero or under the oxygen partial pressure up to the value double said pressure in the stage of sputtering Co-Cr on the oxygen partial pressure versus saturation magnetization characteristic curve of the Co-Cr oxide film deposited on the nonmagnetic substrate.