| 摘要 |
PROBLEM TO BE SOLVED: To enhance an adhesion property of an NiP layer and to strengthen the NiP layer against an impact by film-forming the NiP layer by sputtering specifying the thickness at a specified temperature of a substrate to a specified range. SOLUTION: A magnetic disk is constituted of a magnetic layer 5 provided on a non-magnetic substrate 1 via a substrate 4. Here, the substrate 4 interposed between the non-magnetic substrate 1 and the magnetic layer 5 consists of a Cr adhesive layer 6 adjacent to the substrate 1 and containing Cr, an NiP layer 2 film-formed on the Cr adhesive layer 6 by sputtering and a Cr substrate 3 formed on the NiP layer 2. When the temperature of the substrate and the thickness of the NiP layer 2 are T( deg.C) and (t) nm respectively, a boarder line between combinations of high and low adhesion properties can be approximately expressed by the formula: T=-t+370 in a 40-200 nm range of the thickness of the NiP layer 2. A region where the high adhesion property can be obtained is the region which is located below the boarder line and satisfies the formula T<=-t+370. I.e., the relation: T+t<=370 is formed.
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