Using inductance to measure writer spacing in perpendicular magnetic recording
US7538961B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 2007 |
| Grant date | May 26, 2009 |
| Priority date | — |
| Expiry date | Jun 20, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/3133
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic data recording system that can directly measure soft underlayer spacing of a perpendicular magnetic write head during operation. The soft underlayer spacing of the magnetic write head can be determined by measuring the magnetic inductance of the write head. The inductance of the write head varies with changes in the distance between the write pole and the soft underlayer of the magnetic medium. By connecting the write head with magnetic inductance measuring circuitry, the soft underlayer spacing can be constantly monitored during operation of the magnetic data recording system. The system can also include active fly height control such as a thermal fly height control capability. By directly measuring the soft underlayer spacing in real time during use of the data recording system, the actively fly height controlling features can be operated efficiently to precisely maintain a desired spacing between the write pole and the soft underlayer of the magnetic medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.