Magneto-optical recording medium and magneto-optical recording method
US5889740A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1997 |
| Grant date | Mar 30, 1999 |
| Priority date | — |
| Expiry date | Oct 24, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10591
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Featured is a magneto-optical recording medium including a first magnetic layer, a second magnetic layer, a third magnetic layer and a fourth magnetic layer formed one on another in this order. The first, second, third and fourth magnetic layers have Curie points Tc1, Tc2, Tc3 and Tc4, respectively, which satisfy the condition of Tc3<Tc1<Tc2<Tc4, and exhibit a perpendicular magnetic anisotropy in a temperature range between room temperature and their respective Curie points. The first magnetic layer is adapted to be copied with the magnetization state of the second magnetic layer at a temperature higher than a first temperature, but not copied at a temperature not higher than the first temperature. The first temperature is defined as a temperature between room temperature and the Curie point Tc1. The third magnetic layer is adapted to be copied with the magnetization state of the fourth magnetic layer at least at room temperature. The second magnetic layer is adapted to be copied with the magnetization state of the third magnetic layer at least at room temperature and to be influenced by a magnetic field from the fourth magnetic layer so as to have a magnetization direction determi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.