JPS6476525A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To substantially prevent the breakage of a magnetic recording medium against impact by collision against a magnetic head, etc., and to improve the durability of said medium by laminating a magnetic recording layer consisting of a thin ferromagnetic metallic film and protective film layer successively on an underlying layer consisting of hard carbon on a nonmagnetic substrate. CONSTITUTION:The underlying layer 9 consisting of the hard carbon is formed on the nonmagnetic substrate 8 and the magnetic recording layer 11 consisting of the thin ferromagnetic metallic film and the protective film layer 12 are successively laminated thereon. The material of the nonmagnetic substrate 8 is adequately an Al-Mg alloy. The film thickness of the underlying layer 9 consisting of the hard carbon is adequately 200-2000Angstrom in terms of the prevention of the breakage of the magnetic recording layer and the relation with the strain by residual stress. The orientability of a Co-Ni film is improved if the underlying layer 10 consisting of Cr is provided between the substrate and the underlying layer 9 consisting of the hard carbon particularly in the case of using the Co-Ni alloy for the magnetic recording layer 11. The output decreases if the thickness of the protective effect is not obtainable if the thickness is too small; therefore, the preferable thickness is about 50-2000Angstrom . The breakage of the magnetic recording layer is thereby eliminated and the durability thereof is improved.