| 摘要 |
PURPOSE:To obtain a vertical magnetic recording medium having good reproducibility and remarkably improved running durability by providing a protective layer on the surface of a magnetic layer after forming an oxide layer or nitride layer thereon. CONSTITUTION:A vertically magnetized film having the axis of easy magnetization in the direction perpendicular to the film plane, for example, Co-Cr film is formed by, so-called, thin film forming system such as sputtering, vacuum deposition or ion polating on one or both faces of a nonmagnetic substrate. The surface of the formed magnetic layer is subjected to an oxidation or nitriding treatment and thereafter, the protective layer is provided thereon. The oxidation or nitriding treatment may be executed by a glow discharge treatment inn the presence of oxygen or nitrogen or reverse sputtering in the presence of oxygen or nitrogen. Implantation of oxygen ions or nitrogen ions onto the surface of the magnetic layer by using an ion gun is equally satisfactory. Carbon, SiO2, Co-O-Cr, Cr-O, etc. are used as the protective layer and above all, the carbon is more particularly preferable. The preferable film thickness of the protective film is 0.002-0.1mum, more particularly 0.005-0.05mum.
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