| 摘要 |
PURPOSE:To improve the recording and reproducing characteristic, massproductivity and yield of the title vertical magnetic recording medium by allowing the magnetostatic characteristic of the vertical magnetic anisotropic film to satisfy the specified conditions. CONSTITUTION:The value Ho/Ms is regulated to <=3.5pi, where Ho is the magnetic field at the intersection between a straight line of magnetization M=saturation magnetization Ms and a straight line having the same inclination as the inclination between the abscissa and a hysteresis curve vertical to the surface of a vertical magnetic anisotropic film in a vertical magnetic recording medium and measured by a vibrational sample-type magnetometer and further passing the origin and Ms is the saturation magnetization. Besides, the ratio of the residual magnetization Mr1 vertical to the film surface in the hysteresis curve to the residual magnetization Mr11 in the film plane, Mr1/Mr11, is regulated to 0.2-0.98. At >=3.5pi Ho/Ms, both low-pass reproducing output and D50 are rapidly decreased. meanwhile, a Co-Cr vertical magnetic anisotropic film having high low-pass reproducing output and D50 can be obtained at 0.2-0.98 Mr1/Mr11. In this case, D50 is the recording density when the reproducing output value becomes the half of the output at 1 KFRPI.
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