Magnetic recording media with antiferromagnetically coupled ferromagnetic films as the recording layer
US6280813A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 1999 |
| Grant date | Aug 28, 2001 |
| Priority date | — |
| Expiry date | Oct 8, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/678
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films antiferromagnetically coupled together across a nonferromagnetic spacer film. The magnetic moments of the two antiferromagnetically-coupled films are oriented antiparallel, 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. This reduction in Mrt is accomplished without a reduction in the thermal stability of the recording medium because the volumes of the grains in the antiferromagnetically-coupled films add constructively. In a magnetic recording rigid disk application, the magnetic layer comprises two ferromagnetic films, each a granular film of a sputter deposited CoPtCrB alloy, separated by a Ru spacer film having a thickness to maximize the antiferromagnetic exchange coupling between the two CoPtCrB films. One of the ferromagnetic films is made thicker than the other, but the thicknesses are chosen so that the net moment in zero applied magnetic field is low, but nonzero.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.