Perpendicular magnetic recording medium
US4966821A · kind A · utility
13Cited by
6References
2Claims
0Family size
Assignees
Inventors
Key dates
| Filing date | Jun 27, 1989 |
| Grant date | Oct 30, 1990 |
| Priority date | — |
| Expiry date | Jun 27, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12465
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A perpendicular magnetic recording medium is disclosed, which comprises a substrate, a soft magnetic layer formed on the substrate, a lower recording layer having a coercive force of Hcl formed on the soft magnetic layer, and an upper recording layer having a coercive force of Hcu, with the coercive ratio of Hcu/Hcl being in the range of 1.4 to 3.3, that is, 1.4.ltoreq.Hcu/Hcl.ltoreq.3.3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.