Magneto-optical recording medium and reproducing method for reproducing magnetic domain in enlarged form on a reproducing layer
US6385140B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 2001 |
| Grant date | May 7, 2002 |
| Priority date | — |
| Expiry date | Mar 7, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10593
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optic recording medium includes a second auxiliary magnetic film, a first auxiliary magnetic film and a magneto-optic recording film on a substrate. The auxiliary magnetic films change from in-plane magnetization to vertical magnetization at critical temperatures TCR1 and TCR2. Since they have the relation TCR1>TCR2, the magnetic domain transferred from the magneto-optic recording film to the first auxiliary magnetic film at the time of reproduction is expanded in diameter and is transferred to the second auxiliary magnetic film when the temperature profiles of the auxiliary magnetic films inside an optical spot are utilized. The magnetic domain of the magneto-optic recording film can be expanded and transferred, too, by means of magnetostatic coupling by using a non-magnetic film in place of the first auxiliary magnetic film. Pulse reproduction light subjected to power modulation in synchronism with a reproduction clock can be used at the time of reproduction. Even when a very small magnetic domain is recorded, the intensity of an amplified reproduction signal can be detected and excellent C/N can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.