Patent US4894741A successfully refreshed from Google Patents.
US4894741A
Expired / Lapsed
US
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Magneto-resistive head with improved sensitivity
Assignee: Eastman Kodak Co
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Filing: 1988-05-06
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Granted: 1990-01-16
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Expires: 2008-05-06
Abstract
Abstract To provide optimized performance in a magneto-resistive head having a soft adjacent magnetic biasing layer separated from a current-carrying magneto-resistive sense film by an extremely thin electrically insulating film, the invention provides that the soft adjacent magnetic biasing layer be comprised of a magnetically soft layer of high electrical resistivity, whereby the effect of pinholes in the electrically insulating film is significantly lessened.
Inventors
- 👤 William W. French
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:15
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/399
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
83 words
In a magneto-resistive head of the type having a. a field-responsive sense film of magnetic material adapted to carry a sense current, b. a relatively electrically non-conductive film layered with said sense film of magnetic material, c. a magnetic biasing layer of magnetic material covering said relatively electrically non-conductive film, the improvement wherein said magnetic biasing layer has a resistivity substantially greater than the resistivity of said sense film, and d. said relatively electrically non-conductive film is less than 50 Angstroms in thickness.
Claim 2
Dependent Claim
83 words
In a magneto-resistive head of the type having a. a field-responsive sense film of magnetic material adapted to carry a sense current, b. a relatively electrically non-conductive film layered with said sense film of magnetic material, c. a magnetic biasing layer of magnetic material covering said relatively electrically non-conductive film, the improvement wherein said magnetic biasing layer has a resistivity substantially greater than the resistivity of said sense film, and d. said relatively electrically non-conductive film is less than 50 Angstroms in thickness.
Claim 3
Dependent Claim
25 words
The magneto-resistive head of claim 1 wherein said sense film is comprised of Permalloy, and wherein said magnetic biasing layer is comprised of amorphous Alfesil.
Claim 4
Dependent Claim
39 words
The magneto-resistive head of claim 1 wherein a. said relatively electrically non-conductive film is less than 50 Angstroms in thickness, b. said sense film is comprised of Permalloy, and c. said magnetic biasing film is comprised of amorphous Alfesil.
Claim 5
Dependent Claim
30 words
The magneto-resistive head of claim 3 wherein the resistivity of said Permalloy is about 20×10 -6 Ωcm, and the resistivity of said amorphous Alfesil is greater than 500×10 -6 Ωcm.
References Cited (Backward Citations)
US4663685A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-15 | 1993-07-17 | 1994-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-15 | 1997-07-17 | 1998-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-15 | 2001-07-17 | 2002-01-16 | $7700.00 | Window Closed / Lapsed |