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US 5,686,177 AGranted
Magnetic recording medium
AssigneeHitachi, Ltd.
InventorsKazusuke Yamanaka, Hideo Kusada, Toyoji Okuwaki
Life of this patent
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Abstract
A magnetic recording medium having an improved S/N is provided by using a ferromagnetic metal thin film having a mean value of a fluctuation field of magnetic viscosithy measured at 25.degree. C. in a region in which an applied magnetic field strength is 0.8 to 1.2 times as large as a remanence coercivity, of between 15 Oersteads and 30 Oersteads, and preferably a coercivity of between 700 Oersteads and 2000 Oersteads.
Claims8
A magnetic recording medium comprising:
- a magnetic layer having at least one ferromagnetic cobalt-based thin film, the fluctuation field of said layer of a predetermined magnetic viscosity measured at 25.degree. C. and at a magnetic field equal to a predetermined remanence coercivity being between 15 Oersteads and 30 Oersteads;
- the magnetic layer having a coercivity of between 700 Oerstead and 2000 Oersteads;
- and
- the thickness of said magnetic layer being between 0.1 and 0.18 .mu.m.
1 more element
A magnetic recording medium comprising:
- a magnetic layer having at least one ferromagnetic cobalt-based thin film, the fluctuation field of said layer of a predetermined magnetic viscosity measured at 25.degree. C. and at magnetic field equal to a predetermined remanence coercivity being between 20 Oersteads and 30 Oersteads;
- the magnetic layer having a coercivity of between 700 Oerstead and 2000 Oersteads;
- and
- the thickness of said magnetic layer being between 0.1 and 0.18 .mu.m.
1 more element
A magnetic recording apparatus comprising:
- a magnetic head having a ferromagnetic thin film in a portion of a magnetic pole thereof;
- and
- a magnetic recording medium having a ferromagnetic cobalt-based thin film as a magnetic layer;
- said thin film of said magnetic recording medium having a mean value of a fluctuation field of a predetermined magnetic viscosity at 25.degree. C. and a magnetic field equal to a predetermined remanence coercivity which is between 15 Oersteads and 30 Oersteads;
- said magnetic layer of said magnetic recording medium having a coercivity of between 700 Oersteads and 2,000 Oersteads;
- and
- said magnetic layer of said magnetic recording medium having a thickness of between 0.1 and 0.18 .mu.m.
4 more elements
A magnetic recording apparatus comprising:
- a magnetic head having a ferromagnetic thin film in a portion of a magnetic pole thereof;
- and
- a magnetic recording medium having a ferromagnetic cobalt-based thin film as a magnetic layer;
- said thin film of said magnetic recording medium having a mean value of a fluctuation field of a predetermined magnetic viscosity at 25.degree. C. and at an applied magnetic field equal to a predetermined remanence coercivity which is between 20 Oersteads and 30 Oersteads;
- said magnetic layer of said magnetic recording medium having a coercivity of between 700 Oersteads and 2,000 Oersteads;
- and
- said magnetic layer of said magnetic recording medium having a thickness of between 0.1 and 0.18 .mu.m.
4 more elements
Dependencies are inferred from the claim text.