Magnetic field sensing system using spin-torque diode effect
US8416539B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 2008 |
| Grant date | Apr 9, 2013 |
| Priority date | — |
| Expiry date | May 8, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F10/3259
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic field sensing system with a current-perpendicular-to-the-plane (CPP) sensor, like that used for giant magnetoresistive (GMR) and tunneling magnetoresistive (TMR) spin-valve (SV) sensors, operates in a mode different from conventional GMR-SV and TMR-SV systems. An alternating-current (AC) source operates at a fixed selected frequency and directs AC perpendicularly through the layers of the CPP sensor, with the AC amplitude being high enough to deliberately induce a spin-torque in the CPP sensor's free layer. The AC-induced spin-torque at the selected frequency causes oscillations in the magnetization of the free layer that give rise to a DC voltage signal VDC. VDC is a direct result of only the oscillations induced in the free layer. The value of VDC will change in response to the magnitude of the external magnetic field being sensed and as the free layer is driven in and out of resonance with the AC.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.