| 摘要 |
PROBLEM TO BE SOLVED: To enhance a coercive force and to achieve a high surface recording density by a method wherein an alloy magnetic layer in a magnetic recording medium in which a substrate layer and the alloy magnetic layer are provided on a nonmagnetic substrate is formed in such a way that carbon at specific atomic % or higher is contained over the whole region in its thickness direction. SOLUTION: A nonmagnetic substrate in which an NiP plating treatment is executed to its surface and whose surface is polished is set inside a sputtering apparatus whose vacuum is evacuated in advance down to 5×10<6> Pa, and it is heated at about 250 deg.C. Then, a gas in the ratio of 14 of H2 to 86 of high- purity Cr is introduced into a pure Cr substrate layer, a Co-based magnetic layer and a hydrogenated carbon protective layer in this sequence, and the respective layers are formed continuously. In this case, a substrate temperature is kept at 200 deg.C or higher, the film thickness of the Cr substrate layer is set at 300Å, that of the Co-based magnetic layer is set at 200Å, and that of the hydrogenated carbon protective layer is set at 150Å. At this point, carbon becomes 0.5 atomic % or higher over the whole region in the thickness direction of the Co-based magnetic layer. Thereby, a coercive force can be enhanced, and a high surface recording density can be achieved.
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