| 摘要 |
PURPOSE:To securely stick a magnetic material to a substrate and to remarkably improve the coercive force of the magnetic material by using a chromium film as an underlying layer. CONSTITUTION:The underlying layer essentially consisting of chromium is provided on the substrate and the magnetic layer consisting of a cobalt-platinum alloy is provided on the underlying layer. The thickness of the underlying layer consisting of the chromium film is preferably in a 10-10,000Angstrom range. The effect of improving the coercive force is low and the ratio of the fluctuation of the coercive force to the change of the thickness is high if the thickness is <=10Angstrom . The magnetic recording medium having the stable coercive force is then not obtainable. The coercive force is substantially high and the fluctuation of the coercive force as compared to the change of the thickness is relatively small if the thickness of the chromium layer is within the 100-10,000Angstrom range and therefore, said range is more particularly preferable in general. There is no particular improvement of the coercive force if the chromium layer is made thicker than the specified range. In addition, such is uneconomical.
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