Spin valves with antiferromagnetic exchange pinning and high uniaxial anisotropy reference and keeper layers
US6117569A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 1998 |
| Grant date | Sep 12, 2000 |
| Priority date | — |
| Expiry date | May 27, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1121
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An SV sensor having a reference (pinned) layer formed of a first high uniaxial anisotropy ferromagnetic material, such as Co--Fe, and a keeper layer formed of a second high uniaxial anisotropy ferromagnetic material, such as Ni--Fe--Nb. Lapping induced stress in the high positive magnetostriction Co--Fe layer generates a uniaxial anisotropy field in the pinned layer resulting in enhanced pinned layer magnetization. This uniaxial anisotropy field adds to the exchange field from an antiferromagnetic layer resulting in a substantially increased pinning field over the pinning field from the exhange interaction alone. The added uniaxial anisotropy field also improves the stability of the SV sensor at elevated temperatures since the uniaxial field is determined by a Curie temperature significantly higher than the blocking temperatures of antiferromagnetic materials. Lapping induced stress in the high positive magnetostriction Ni--Fe--Nb layer generates a uniaxial anisotropy field in the keeper layer providing more uniform magnetization and therefore better flux cancellation. The high electrical resistivity of the Ni--Fe--Nb keeper layer has the further benefit of reducing sense current s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.