| 摘要 |
PURPOSE:To obtain high reproduction output even at >=180KFRPI recording density by forming a magnetic layer essentially consisting of Co and Cr and consisting of additives which are Ni and at least one element among Cu, P and Al and trace impurities in such a manner that the concn. of Cu, P and Al or the concn. of Ni and Cu, P, Al near the substrate is lower than the average concn. over the entire part of the film. CONSTITUTION:The magnetic layer essentially consisting of Co and Cr and consisting of the additives which are Ni and at least one element along Cu, Al, and P and trace impurities is formed on the substrate in such a manner that the concn. of Cu, Al and P or the concn. of Ni and Cu, Al and P is lower than the average concn. over the entire part of the film. The film having such constitution has the high reproduction output even at the substrate temp. below 100 deg.C at which a PE terephthalate is usable as the substrate and at >=180KFRPI recording density.
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