Perpendicular magnetic recording medium, and perpendicular magnetic recording and reproducing apparatus
US7879466B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 29, 2006 |
| Grant date | Feb 1, 2011 |
| Priority date | — |
| Expiry date | Dec 25, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F10/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention provides a perpendicular recording medium with high recording density, and a magnetic recording and reproducing apparatus, by improving the function of magnetic anisotropy of a soft magnetic underlayer. The perpendicular recording medium has at least a soft magnetic underlayer and a perpendicular magnetic recording layer on a non-magnetic substrate, wherein when Ku⊥ (erg/cm3) is defined as a perpendicular magnetic anisotropic energy, and Ms (emu/cm 3) is defined as a saturation magnetization of the soft magnetic underlayer, Ku⊥ of the soft magnetic underlayer has a negative value and Ku⊥<−2πMs2. As a result, the easy axis of a magnetization of a soft magnetic underlayer is oriented strongly in the substrate surface plane, which is effective to suppress the WATE phenomena and spike noise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.