Implementing spin torque oscillator power-on oscillation checker using ramped STO bias differentiator in microwave-assisted magnetic recording (MAMR) hard disk drives
US8917465B1 · kind B1 · utility
19Cited by
8References
20Claims
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Key dates
| Filing date | Jun 26, 2014 |
| Grant date | Dec 23, 2014 |
| Priority date | — |
| Expiry date | Jun 26, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2005/0024
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method, apparatus, and system are provided for implementing a power-on spin-torque oscillator (STO) oscillation checker to monitor STO resistance to identify STO oscillation with microwave assisted magnetic recording (MAMR) hard disk drives (HDDs). A changing bias current is applied to the STO in the presence of constant write drive current. The STO bias current is changed to observe sudden changes in STO resistance monitored using a differentiator circuit to identify STO oscillation, used to ensure stable MAMR HDD write operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.