Testing method and apparatus of thin-film magnetic head
US7545139B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2007 |
| Grant date | Jun 9, 2009 |
| Priority date | — |
| Expiry date | Oct 30, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/455
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A testing method of a thin-film magnetic head has an MR read head element with a multi-layered structure including a magnetization-fixed layer, a magnetization-free layer and a nonmagnetic intermediate layer or a tunnel barrier layer sandwiched between the magnetization-fixed layer and the magnetization-free layer. The method includes a step of feeding through the MR read head element a sense current, a step of measuring non-signal output versus frequency characteristics of the MR read head element over a frequency range that covers at least FMR of the magnetization-fixed layer, and a step of discriminating whether the thin-film magnetic head is a head providing high-temperature noises by comparing a frequency of a peak of the non-signal output resulting from FMR of the magnetization-fixed layer with a threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.