Magneto-optical recording medium having multiple magnetic layers
US6826131B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 2001 |
| Grant date | Nov 30, 2004 |
| Priority date | — |
| Expiry date | Jul 22, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10584
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A multilayer film including a first magnetic layer, a second magnetic layer, and a third magnetic layer in the stated order is formed so that a Curie temperature TC2 of the second magnetic layer is set to be lower than a Curie temperature TC1 of the first magnetic layer and a Curie temperature TC3 of the third magnetic layer and that the third magnetic layer is a perpendicular magnetization film. In at least a part of a region at a temperature lower than TC2, the first magnetic layer is perpendicularly magnetized by exchange coupling with the second magnetic layer, and the magnetization of the third magnetic layer is transferred to the first magnetic layer via the second magnetic layer because of the exchange coupling. The second magnetic layer is made of a magnetic layer that remains in an in-plane magnetization state at room temperature and is perpendicularly magnetized in a temperature range from a critical temperature TCR higher than room temperature to the Curie temperature TC2 of the same. Thus, in a magneto-optical recording medium to which the magnetic-domain enlarging-reproducing method is applied, upon reproduction of information utilizing the magnetic-domain enlargement,…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.