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US 6,805,981 B2Granted
Perpendicular magnetic recording medium and perpendicular magnetic recording-reproducing apparatus
AssigneesKabushiki Kaisha Toshiba, Showa Denko K.K.
InventorsHideo Ogiwara, Takashi Hikosaka, Soichi Oikawa, Hiroshi Sakai, Kenji Shimizu
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Abstract
A perpendicular magnetic recording medium comprising a layer exhibiting a super paramagnetism is used as the underlying film to enable the recording medium to achieve a high density recording with a low noise.
Claims18
A perpendicular magnetic recording medium comprising:
- a nonmagnetic substrate;
- an underlying film formed on said nonmagnetic substrate;
- and
- a perpendicular magnetic layer formed on said underlying film,
- wherein said underlying film has a layer exhibiting a super paramagnetism, and the magnetization of said layer exhibiting super paramagnetism is not larger than 20 emu/cm2 when a magnetic field of 796,000 A/m is applied at 300K.
2 more elements
A perpendicular magnetic recording-reproducing apparatus comprising:
- a perpendicular magnetic recording medium;
- driving means for supporting and rotating the perpendicular magnetic recording medium;
- a magnetic head including an element for recording information in the perpendicular magnetic recording medium and an element for reproducing the recorded information;
- and
- a carriage assembly supporting said magnetic head which is movable relative to the perpendicular magnetic recording medium,
- wherein the perpendicular magnetic recording medium comprises:
- a nonmagnetic substrate,
- an underlying film formed on the nonmagnetic substrate and having a layer exhibiting super paramagnetism, and the magnetization of said layer exhibiting super paramagnetism is not larger than 20 emu/cm2 when a magnetic field of 796,000 A/m is applied at 300K and
- a perpendicular magnetic layer formed on the underlying film.
6 more elements
Dependencies are inferred from the claim text.