| 摘要 |
PURPOSE:To obtain superior magnetic characteristics and the uniformity of outputs by coating a metallic base plate with a nonmagnetic metallic layer or a nonmagnetic metallic oxide layer, coating the layer with a metallic thin film medium including cobalt or platinum through a coating film and then covering the surface of the medium with a protective film. CONSTITUTION:The surface of the metallic base plate 1 is coated with nickel- phosphorus alloy as the nonmagnetic metallic layer 2 by plating and the surface of the layer 2 is mirror finished to 0.03mum or less maximum surface roughness. Subsequently, the surface of the layer 2 is coated with a coating film such as polysilicon by spin-coating the alcohol solution of terahydroxysilane e.g. The surface of the film 3 is coated with the metallic magnetic medium 4 including cobalt and platinum such as Co-Pt alloy by sputtering or the like. Said medium 4 shows superior hysteresis in the ranges of 500-1,700oe coercive force, 15,000- 3,000G saturated magnetic flux density and 0.8-0.97 square ratio. The surface roughness of the coating film 3 is 50Angstrom or less, so that the uniformity of the medium, especially SN, is improved. Metal such as osmium or oxicide or nitrate such as silicon is preferable to the protective film. |
