| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to decrease medium noises and to obtain a high S/N and stable recording signals by disposing a Cr alloy ground surface layer essentially consisting of Cr and containing at least Ta between a hard magnetic pinning layer and a nonmagnetic substrate. SOLUTION: The vertical magnetic recording medium consists of a four- layered structure formed by successively laminating the Cr alloy ground surface layer, the hard magnetic pinning layer, a soft magnetic ground surface layer and a vertical recording layer on the nonmagnetic substrate. The Cr alloy ground surface layer is a ground surface for the hard magnetic pinning layer to be formed thereon and at least Ta is incorporated into the Cr alloy to impart uniaxial magnetic anisotropy in the radial direction of the disk-shaped medium, by which Hc is enhanced. The influence by incoming magnetic fields can be lessened and the pinning effect of the hard magnetic pinning layer is improved by specifying the content of the Ta to >=6 at.%. The hard magnetic pinning layer is formed of Co or CoNi, CoNiCr, etc., on the Cr-based alloy ground surface layer.
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