US5014147A
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Magnetoresistive sensor with improved antiferromagnetic film
Assignee: International Business Machines Corp
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Filing: 1989-10-31
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Granted: 1991-05-07
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Expires: 2009-10-31
Abstract
Abstract An improved thin film magnetoresistive (MR) sensor uses an alloy comprising Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4, as an antiferromagnetic layer to provide longitudinal exchange bias in the ferromagnetic MR layer. In a specific embodiment the exchange bias is at a high level and is independent of thickness of the antiferromagnetic layer over a wide range.
Inventors
- 👤 Stuart S. P. Parkin
- 👤 Kevin P. Roche
- 👤 Virgil S. Speriosu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:29
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; G01R33/09; G01R33/093; B; B82; B82Y; B82Y25/00; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3929; G11B5/3932; G11B5/399
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
58 words
An improved magnetoresistive sensor of the type having an antiferromagnetic layer in direct contact with a magnetoresistive ferromagnetic layer for inducing a longitudinal bias in the ferromagnetic layer, wherein the improvement is an antiferromagnetic layer comprising an alloy of manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4.
Claim 2
Dependent Claim
58 words
An improved magnetoresistive sensor of the type having an antiferromagnetic layer in direct contact with a magnetoresistive ferromagnetic layer for inducing a longitudinal bias in the ferromagnetic layer, wherein the improvement is an antiferromagnetic layer comprising an alloy of manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4.
Claim 3
Dependent Claim
18 words
The magnetoresistive sensor according to claim 1 wherein said ferromagnetic layer is an alloy comprising nickel and iron.
Claim 4
Dependent Claim
20 words
The magnetoresistive sensor according to claim 2 wherein ferromagnetic layer alloy comprises about 80 percent nickel and about 20% iron.
Claim 5
Dependent Claim
104 words
A magnetoresistive read sensor comprising: a thin magnetoresistive layer of ferromagnetic material; a thin layer of antiferromagnetic material in direct contact with said magnetoresistive layer for inducing a magnetic exchange bias in said magnetoresistive layer, said antiferromagnetic material being an alloy of manganese (Mn) and iron (Fe) Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4; and means for producing a transverse bias in said magnetoresistive layer whereby, upon connection of a sensing means to said magnetoresistive layer, resistance changes in said magnetoresistive layer can be determined as a function of the magnetic fields intercepted by said magnetoresistive layer.
Claim 6
Dependent Claim
104 words
A magnetoresistive read sensor comprising: a thin magnetoresistive layer of ferromagnetic material; a thin layer of antiferromagnetic material in direct contact with said magnetoresistive layer for inducing a magnetic exchange bias in said magnetoresistive layer, said antiferromagnetic material being an alloy of manganese (Mn) and iron (Fe) Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4; and means for producing a transverse bias in said magnetoresistive layer whereby, upon connection of a sensing means to said magnetoresistive layer, resistance changes in said magnetoresistive layer can be determined as a function of the magnetic fields intercepted by said magnetoresistive layer.
Claim 7
Dependent Claim
17 words
The sensor according to claim 4 wherein said magnetoresistive layer is an alloy comprising nickel and iron.
Claim 8
Dependent Claim
20 words
The sensor according to claim 5 wherein said magnetoresistive layer alloy comprises about 80 percent nickel and about 20% iron.
Claim 9
Dependent Claim
103 words
A magnetoresistive read sensor comprising: a thin layer of antiferromagnetic material comprising an alloy of Manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4; a thin magnetoresistive layer of ferromagnetic material in direct contact with said antiferromagnetic layer, said antiferromagnetic layer induces a magnetic exchange bias in said magnetoresistive layer; and means for producing a transverse bias in said magnetoresistive layer whereby, upon connection of a sensing means to said magnetoresistive layer, resistance changes in said magnetoresistive layer can be determined as a function of the magnetic fields intercepted by said magnetoresistive layer.
Claim 10
Dependent Claim
103 words
A magnetoresistive read sensor comprising: a thin layer of antiferromagnetic material comprising an alloy of Manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4; a thin magnetoresistive layer of ferromagnetic material in direct contact with said antiferromagnetic layer, said antiferromagnetic layer induces a magnetic exchange bias in said magnetoresistive layer; and means for producing a transverse bias in said magnetoresistive layer whereby, upon connection of a sensing means to said magnetoresistive layer, resistance changes in said magnetoresistive layer can be determined as a function of the magnetic fields intercepted by said magnetoresistive layer.
Claim 11
Dependent Claim
19 words
The sensor according to claim 7 wherein said magnetoresistive layer is a magnetoresistive layer alloy comprising nickel and iron,
Claim 12
Dependent Claim
20 words
The sensor according to claim 8 wherein said magnetoresistive layer alloy comprises about 80 percent nickel and about 20% iron.
Claim 13
Dependent Claim
29 words
The sensor according to claim 7 additionally comprising an auxiliary layer prior to said layer of antiferromagnetic material, said auxiliary layer comprising a material having a face-centered cubic structure.
Claim 14
Dependent Claim
12 words
The sensor according to claim 10 wherein said auxiliary layer comprises copper.
Claim 15
Dependent Claim
60 words
The sensor according to claim 10 additionally comprising a second layer of antiferromagnetic material in direct contact with said layer of ferromagnetic material for inducing a further magnetic exchange bias in said magnetoresistive layer, said antiferromagnetic material comprising an alloy of manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4.
Claim 16
Dependent Claim
60 words
The sensor according to claim 7 additionally comprising a second layer of antiferromagnetic material in direct contact with said layer of ferromagnetic material for inducing a further magnetic exchange bias in said magnetoresistive layer, said antiferromagnetic material comprising an alloy of manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4.
Claim 17
Dependent Claim
113 words
A magnetoresistive read sensor comprising: a substrate; a thin layer of antiferromagnetic material upon said substrate, said thin film of antiferromagnetic comprising an alloy of Manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4; a thin magnetoresistive layer of ferromagnetic material in direct contact with said antiferromagnetic layer said antiferromagnetic layer induces a magnetic exchange bias in said magnetoresistive layer; and means for producing a transverse bias in said magnetoresistive layer whereby, upon connection of a sensing means to said magnetoresistive layer, resistance changes in said magnetoresistive layer can be determined as a function of the magnetic fields intercepted by said magnetoresistive layer.
Claim 18
Dependent Claim
113 words
A magnetoresistive read sensor comprising: a substrate; a thin layer of antiferromagnetic material upon said substrate, said thin film of antiferromagnetic comprising an alloy of Manganese (Mn) and iron (Fe), Fe.sub.(1-x) Mn x , where x is within the range of 0.3 to 0.4; a thin magnetoresistive layer of ferromagnetic material in direct contact with said antiferromagnetic layer said antiferromagnetic layer induces a magnetic exchange bias in said magnetoresistive layer; and means for producing a transverse bias in said magnetoresistive layer whereby, upon connection of a sensing means to said magnetoresistive layer, resistance changes in said magnetoresistive layer can be determined as a function of the magnetic fields intercepted by said magnetoresistive layer.
Claim 19
Dependent Claim
31 words
The sensor according to claim 14 wherein said substrate has a surface which does not comprise a face-centered cubic structure, said thin film of antiferromagnetic material being deposited upon said surface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-05-06 | 1994-11-05 | 1995-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-06 | 1998-11-05 | 1999-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-06 | 2002-11-05 | 2003-05-07 | $7700.00 | Window Closed / Lapsed |