Magnetic sensors having an antiferromagnetic layer exchange-coupled to a free layer
US6542341B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 18, 1999 |
| Grant date | Apr 1, 2003 |
| Priority date | — |
| Expiry date | Nov 18, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2005/3996
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic sensor which detects an external magnetic field with the aid of a ferromagnetic free layer having a magnetic moment responsive to the external magnetic field. The magnetic sensor has an antiferromagnetic layer which is magnetically exchange-coupled to the free layer to produce an exchange bias field He which acts on the free layer to bias its magnetic moment along a certain orientation such as the transverse direction. The additional exchange bias field He is used in balancing a total transverse internal magnetic field Ht which is due to other fields generated by the sensor itself. The value of exchange bias field He is set, e.g., by selecting a certain thickness and a certain composition of the antiferromagnetic layer. The magnetic sensor of the invention can also have a non-magnetic spacer layer interposed between the free layer and the antiferromagnetic layer or be in contact with the free layer. The sensor can be a spin valve sensor, a tunnel valve sensor, or any magnetic sensor using the free layer and the magnetoresistive effect to detect the external magnetic field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.