US5313186A
Expired / Lapsed
US
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Sensor of weak magnetic fields, with magnetoresistive effect
Assignee: Thales SA
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Filing: 1992-12-16
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Granted: 1994-05-17
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Expires: 2012-12-16
Abstract
Abstract A sensor of weak magnetic fields with magnetoresistive effect features a metallic multilayer formed by alternating magnetic and non-magnetic metals. In order to detect weak fields, a sensor is described wherein a magnetic field is coupled by an anti-ferromagnetic type coupling with a first neighboring magnetic layer and by a ferromagnetic type coupling with a third neighboring magnetic layer, so that there is frustration of coupling. The first and third magnetic layers are blocked by their strong coercive field. The sensor finds particular application to detection on magnetic media.
Inventors
- 👤 Alain Schuhl
- 👤 Stephane Tyc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:03
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; G01R33/09; G01R33/093; B; B82; B82Y; B82Y25/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
153 words
A sensor of magnetic fields with magnetoresistive effect comprising: a first layer of magnetic material being magnetized in a first predetermined direction; a second layer of magnetic material being magnetized in a second predetermined direction opposite to the first predetermined direction; a third layer of magnetic material being magnetized in a first predetermined direction; wherein the second layer of magnetic material is formed between the first and third layers of magnetic material; a first layer of non-magnetic material formed between the first and second layers of magnetic material; a second layer of non-magnetic material formed between the second and third layers of magnetic material; and wherein a thickness of the first layer of non-magnetic material is different than a thickness of the second layer of non-magnetic material, thereby the first and second layers of magnetic material being anti-ferromagnetically coupled together and the second and third layers of magnetic material being ferromagnetically coupled together.
Claim 2
Dependent Claim
153 words
A sensor of magnetic fields with magnetoresistive effect comprising: a first layer of magnetic material being magnetized in a first predetermined direction; a second layer of magnetic material being magnetized in a second predetermined direction opposite to the first predetermined direction; a third layer of magnetic material being magnetized in a first predetermined direction; wherein the second layer of magnetic material is formed between the first and third layers of magnetic material; a first layer of non-magnetic material formed between the first and second layers of magnetic material; a second layer of non-magnetic material formed between the second and third layers of magnetic material; and wherein a thickness of the first layer of non-magnetic material is different than a thickness of the second layer of non-magnetic material, thereby the first and second layers of magnetic material being anti-ferromagnetically coupled together and the second and third layers of magnetic material being ferromagnetically coupled together.
Claim 3
Dependent Claim
36 words
The sensor according to claim 1, wherein the first and third layers of magnetic material are formed of hard type magnetic materials and the second layer of magnetic material is formed of soft type magnetic materials.
Claim 4
Dependent Claim
41 words
The sensor according to claim 2, wherein the hard type magnetic materials comprise materials selected from the group consisting of Co and Ni, and wherein the soft type magnetic materials comprise materials selected from the group consisting of Fe and NiFe.
Claim 5
Dependent Claim
33 words
The sensor according to any of claims 1-3, wherein the first and second layers of non-magnetic material comprise materials selected from the group consisting of Cu, Ag, Au, Mn, Cr, Va and Ti.
References Cited (Backward Citations)
EP0485129A1
Cited
US5206590A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-16 | 1997-11-15 | 1998-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-16 | 2001-11-15 | 2002-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-16 | 2005-11-15 | 2006-05-17 | $7700.00 | Window Closed / Lapsed |