Low power magnetic anomaly sensor
US6538437B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 2001 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Jun 18, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/04
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A transpinnor-based magnetometer is provided having four resistive elements exhibiting GMR in a bridge configuration. A bias current is applied to the bridge, yielding an output if the bridge is unbalanced due to changes in the GMR resistors. An oscillating magnetic field is applied inductively to the GMR resistors alternately driving them between saturated magnetic states. The drive conductors are physically arranged so that an external magnetic field will oppose the applied field in two resistors and aid the applied field in the other two. The output is nonzero only when the sum of the applied field and external field exceeds the GMR coercivity in one pair of GMR films and not the other. The frequency of the output signal can be varied by switching the polarity of the bias current and controlling the phase with respect to the drive current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.