Magnetic recording medium with antiparallel coupled ferromagnetic films as the recording layer
US6723450B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 2002 |
| Grant date | Apr 20, 2004 |
| Priority date | — |
| Expiry date | Mar 31, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24967
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films with different remanent magnetization-thickness (Mrt) values that are coupled antiparallel across a nonferromagnetic spacer film predominantly by the dipole field (Hd) from the grains of the higher-Mrt ferromagnetic film. The material compositions and thicknesses of the ferromagnetic films and the nonferromagnetic spacer film are selected so that Hd predominates over any antiferromagnetic exchange coupling field (Haf) and is greater than the coercive field of the lower-Mrt ferromagnetic film. As a result, the magnetizations of the two ferromagnetic films are antiparallel in the two remanent magnetic states, and thus the net remanent magnetization-thickness product (Mrt) of the recording layer is the difference in the Mrt values of the two ferromagnetic films.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.