Magneto-optical recording medium having multiple magnetic layers
US7126884B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 7, 2003 |
| Grant date | Oct 24, 2006 |
| Priority date | — |
| Expiry date | May 15, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10515
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a magneto-optical recording medium, a first magnetic layer is made of a material using a Gd—Fe film or a Gd—Fe—Co film as a base so that a magnetic field normalized based on saturation magnetization of a magnetic domain wall driving field can be smaller than 1. A second magnetic layer is made of a material using a Tb—Fe film or a Dy—Fe film as a base, to which a nonmagnetic element such as Al or Cr, and Co are added. A third magnetic layer is made of a material using a Tb—Fe—Co film or a Dy—Fe—Co film as a base, and an element concentration ratio (at. % ratio) of Tb or Dy to Fe—Co is set in a range of 24.5≦Tb≦26.5 or 26.5≦Dy≦29.5. Addition amounts of Co and a nonmagnetic element to each magnetic layer are adjusted to set Curie temperatures Tc11, Tc12, and Tc13 of the first, second and third magnetic layers to Tc13>Tc11>Tc12.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.