Magnetic recording medium including at least one superparamagnetic layer and magnetic storage apparatus
US7074508B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 10, 2004 |
| Grant date | Jul 11, 2006 |
| Priority date | — |
| Expiry date | Aug 10, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/7379
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording medium has a base structure, and a synthetic ferrimagnetic structure which is disposed on the base structure and forms a recording layer. The synthetic ferrimagnetic structure includes at least a bottom magnetic layer and a top magnetic layer which are antiferromagnetically coupled via a nonmagnetic spacer layer. The bottom magnetic layer is made of a superparamagnetic layer, and the top magnetic layer is made of a ferromagnetic material. Magnetic moment orientations of the bottom and top magnetic layers are antiparallel at remanent state where an external applied magnetic field is zero. This is achieved since the bottom magnetic layer is in a reverse saturated state due to exchange coupling at remanence, though coercivity is zero for bottom magnetic layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.