Perpendicular magnetic recording medium and magnetic read/write apparatus
AssigneeKabushiki Kaisha Toshiba
InventorTakashi Hikosaka
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Abstract
Disclosed is a perpendicular magnetic recording medium having magnetic characteristics by which an anisotropic magnetic field Hk and a saturation magnetization Ms satisfy the requirement 2<Hk/4πMs<5, letting α be the inclination of an MH loop when a magnetic field is applied perpendicularly, the anisotropic magnetic field Hk, the saturation magnetization Ms, and a coercive force Hc satisfy the requirement 0.01<{(α−1)Hc+4πMs}/Hk<0.2, and a longitudinal residual magnetization Mr is less than 0.2 times the saturation magnetization Ms.
Claims10
A magnetic recording medium comprising a substrate and a perpendicular magnetic layer formed on said substrate,
- wherein said magnetic recording medium has magnetic recording characteristics by which an anisotropic magnetic field Hk and a saturation magnetization Ms satisfy the condition 2<Hk/4πMs<5 . . . (1), letting α be the inclination of a hysteresis curve representing a change in magnetization M when a magnetic field H is applied in a direction perpendicular to said perpendicular magnetic layer, the anisotropic magnetic field Hk, the saturation magnetization Ms, and a coercive force Hc satisfy the condition 0.01<{(α−1)Hc+4πMs}/Hk<0.2 . . . (2), and a longitudinal residual magnetization Mr is less than 0.2 times the saturation magnetization Ms.
A magnetic read/write apparatus comprising:
- a perpendicular magnetic recording medium;
- a driving mechanism to support and rotate said perpendicular magnetic recording medium;
- and
- a single-pole recording head to write data on said perpendicular magnetic recording medium,
- wherein said perpendicular magnetic recording medium comprises a perpendicular magnetic layer, and has magnetic characteristics by which an anisotropic magnetic field Hk and a saturation magnetization Ms satisfy the condition 2<Hk/4πMs<5 . . . (1), letting α be the inclination of a hysteresis curve representing a change in magnetization M when a magnetic field H is applied in a direction perpendicular to said perpendicular magnetic layer, the anisotropic magnetic field Hk, the saturation magnetization Ms, and a coercive force Hc satisfy the condition 0.01<{(α−1)Hc+4πMs}/Hk<0.2 . . . (2), and a longitudinal residual magnetization Mr is less than 0.2 times the saturation magnetization Ms.
Dependencies are inferred from the claim text.