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US4755897A
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Magnetoresistive sensor with improved antiferromagnetic film
Assignee: International Business Machines Corp
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Filing: 1987-04-28
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Granted: 1988-07-05
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Expires: 2007-04-28
Abstract
Abstract An improved thin film magnetoresistive (MR) sensor uses an alloy comprising Fe, Mn and Cr as an antiferromagnetic layer to provide a longitudinal exchange bias in the ferromagnetic MR layer. Sufficient exchange biasing is provided and the FeMnCr layer exhibits excellent corrosion resistance.
Inventors
- 👤 James K. Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:37
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/399
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
68 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), iron (Fe), and chromium (Cr), with chromium present in the alloy in an amount greater than approximately 3 atomic percent and less than approximately 12 atomic percent.
Claim 2
Dependent Claim
68 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), iron (Fe), and chromium (Cr), with chromium present in the alloy in an amount greater than approximately 3 atomic percent and less than approximately 12 atomic percent.
Claim 3
Dependent Claim
18 words
The improved sensor according to claim 1 wherein said ferromagnetic layer is an alloy comprising nickel and iron.
Claim 4
Dependent Claim
111 words
A magnetoresistive read sensor comprising: a thin magnetoresistive layer of ferromagnetic material; a thin layer of antiferromagnetic material in direct contact with the magnetoresistive layer for inducing a magnetic exchange bias in the magnetoresistive layer, the antiferromagnetic material being an alloy comprising manganese (Mn), iron (Fe), and chromium (Cr), with Cr present in an amount greater than approximately 3 atomic percent and less than approximately 12 atomic percent; 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 5
Dependent Claim
111 words
A magnetoresistive read sensor comprising: a thin magnetoresistive layer of ferromagnetic material; a thin layer of antiferromagnetic material in direct contact with the magnetoresistive layer for inducing a magnetic exchange bias in the magnetoresistive layer, the antiferromagnetic material being an alloy comprising manganese (Mn), iron (Fe), and chromium (Cr), with Cr present in an amount greater than approximately 3 atomic percent and less than approximately 12 atomic percent; 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
17 words
The sensor according to claim 3 wherein said magnetoresistive layer is an alloy comprising nickel and iron.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-05 | 1992-01-04 | 1992-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-05 | 1996-01-04 | 1996-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-05 | 2000-01-04 | 2000-07-05 | $7700.00 | Window Closed / Lapsed |