Photo-thermo-magnetic recording medium and method of preparing same
US4645722A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Sep 21, 1984 |
| Grant date | Feb 24, 1987 |
| Priority date | — |
| Expiry date | Sep 21, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/928
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A recording medium suitable for use in a photo-thermo-magnetic memory of high density recording, including a substrate; a first magnetic layer, such as an amorphous TbFe film, which has a large coercive force and whose axis of easy magnetization is oriented in the direction perpendicular to the surface of the first layer; and a second magnetic layer, such as an amorphous GdTbCoFe film, having (i) a larger polar Kerr rotation or reflection than that of the first layer, (ii) the same polarity of polar Kerr rotation as that of the first layer, (iii) a direction of its magnetic moment aligned in parallel with that of the first layer and (iv) a thickness permitting the transmittance of a light, such as laser beam, therethrough and being magnetically coupled with the first layer by an exchange interaction therebetween; the first and second magnetic layers being superimposed on the substrate in that order or in the inverse order. Such a recording medium can be suitably prepared by re-sputtering or ion-bombardment techniques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.