Perpendicular magnetic recording medium with exchange-coupled magnetic layers and improved coupling layer
US7638210B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 2007 |
| Grant date | Dec 29, 2009 |
| Priority date | — |
| Expiry date | Sep 14, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24942
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A perpendicular magnetic recording medium has an “exchange-spring” type magnetic recording layer (RL) with an improved coupling layer (CL). The RL includes the first or lower ferromagnetic layer MAG1, sometimes called the “media” layer, the second or upper ferromagnetic layer MAG2, sometimes called the “exchange-spring” layer, and the intermediate CL that provides ferromagnetic exchange coupling between MAG1 and MAG2. The CL is formed of NiCr or RuCr based alloys, or CoCr or CoCrB alloys with high Cr and/or B content (Cr plus B>about 25 atomic percent), or RuCoCr alloys with low Co content (<about 65 atomic percent). For each CL composition there is a CL thickness range that provides the optimal interlayer exchange coupling between MAG1 and MAG2. The selected CL materials provide an exchange-type perpendicular magnetic recording medium with good magnetic performance, while the relatively high amount of Cr of the CL improves the corrosion resistance of the medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.