| 摘要 |
PURPOSE: To obtain a magnetic thin film medium having overwritability enhanced toward the outer circumference side and S-N ratio increased toward the inner circumference side by reducing the thickness of a circular magnetic thin film layer formed on a discoid substrate from the inner circumference side toward the outer circumference side by a prescribed value. CONSTITUTION: An underlayer 24 having inner and outer circumferential edges 30, 32, a magnetic thin film layer 26 and a carbon protective film 28 are successively laminated on a discoid substrate 22 to obtain the objective magnetic thin film medium such as a disk. The thickness of the layer 26 is about 500-700Ånear the inner circumference and about 350-550K near the outer circumference and the difference in thickness is 150-300Å. By the structure using the magnetic layer whose thickness becomes smaller from the inner circumference side toward the outer circumference side, the resultant. medium has overwritability gradually enhanced toward the outer circumference side and S-N ratio increased toward the inner circumference side.
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