Device of evaluating magnetic read head and method of evaluating magnetic read head
US7990137B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 30, 2009 |
| Grant date | Aug 2, 2011 |
| Priority date | — |
| Expiry date | Jan 19, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2005/3996
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An MR element having a magnetically free layer and a magnetic bias layer that applies a bias magnetic field to the magnetically free layer are included. Furthermore, a measuring section that measures a ferromagnetic resonance frequency f0 of the magnetically free layer under a condition of applying a predetermined external magnetic field Hm to the magnetically free layer, and an operation section that computes the bias magnetic field Hb according to a following conditional expression (1):Hb={(2*π*f0/γ)2/Ms}−(Hk+Hm) (1)where γ is a gyroscope constant, Ms is a saturation magnetic field of the magnetically free layer, and Hk is a shape anisotropy magnetic field of the magnetically free layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.