Magneto-optical recording medium having a layer that retains its state of magnetization regardless of the presence of an external magnetic field, and a recording/reproducing method therefor
US5450382A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 25, 1994 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Apr 25, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10586
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optical recording medium has at least a first magnetic layer and a second magnetic layer which are mutually exchange-coupled. The first magnetic layer has a compensation temperature within a range higher than a room temperature but lower than the Curie temperature of the second magnetic layer. Under the application of an external magnetic field of a suitable intensity to the recording medium, the magnetization of the first magnetic layer is oriented in a stable direction with respect to the external magnetic field at the room temperature. At the vicinity of the compensation temperature of the first magnetic layer, the magnetization of the first magnetic layer is oriented in a stable direction with respect to the exchanging-coupling with the second magnetic layer. The second magnetic layer maintains a predetermined magnetization state at any temperature from the room temperature to the compensation temperature of the first magnetic layer regardless of the presence or absence of the external magnetic field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.