Magnetic recording medium and a magnetic storage apparatus
US6569545B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1999 |
| Grant date | May 27, 2003 |
| Priority date | — |
| Expiry date | Jun 30, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/90
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic storage device has a recording density of over 5 gigabits per square inch. In the magnetic layer, the magnetic crystal grains of the granular structure are separated by a nonmagnetic phase. The typical crystal grain is in the approximate shape of a sphere or an ellipsoid. The thickness of the magnetic crystal grains, which is in the direction perpendicular to the surface of the film, is smaller than that of the thickness of the magnetic film. The ratio of the coercive force which is measured in the circumferential direction to the coercive force which is measured in the radial direction, which is the orientation ratio of the coercive force, is larger than 1.0, but preferably not greater than 3.0. Further, the area fraction of the magnetic grains having an extended axis within 30° from the circumferential direction is equal to or more than 45%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.