Magnetically soft, high saturation magnetization laminate of iron-cobalt-nitrogen and iron-nickel for perpendicular media underlayers
US7968219B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 2008 |
| Grant date | Jun 28, 2011 |
| Priority date | — |
| Expiry date | Apr 22, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12465
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic disk includes a substrate, a soft magnetic underlayer disposed over the substrate, and a media layer disposed over the underlayer. The underlayer includes a first plurality of layers each containing NiFe having an atomic concentration of iron that is at least about thirty percent. The underlayer further includes a second plurality of layers that is interleaved with the first plurality of layers. The second plurality of layers each contain FeCoN having an atomic concentration of iron that is greater than an atomic concentration of cobalt, and having an atomic concentration of nitrogen that is less than the atomic concentration of cobalt. The atomic concentration of nitrogen is less than eight percent. The media layer contains a magnetically hard material having an easy axis of magnetization oriented substantially perpendicular to both the media layer and the underlayer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.