Patent US3840898A successfully refreshed from Google Patents.
US3840898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-biased magnetoresistive sensor
Assignee: International Business Machines Corp
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Filing: 1972-12-29
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Granted: 1974-10-08
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Expires: 1992-12-29
Abstract
Abstract For high density recording (more than 2000 bits per inch) and magnetic bubble sensing, magnetoresistive heads are being used. To operate them most efficiently, the heads are biased about the most linear range of the R-H plot of the magnetoresistive sensor of the head. Provision is made to have such biasing means be an integral part of the transducer so as to permit one to fabricate miniature sensors.
Inventors
- 👤 C Bajorek
- 👤 L Romankiw
- 👤 D Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:56
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3929; G11B5/3932; G11B5/399
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
82 words
In a magnetic transducer having a thin film layer magnetoresistive strip in magnetic-coupling relationship with the magnetized data of a storage medium, a magnetically hard, permanently magnetized, thin film layer parallel to the plane of said magnetoresistive strip constantly magnetized in the same direction when exposed to Magnetic fields below a predetermined level, adjacent to said magnetoresistive strip for applying a permanent magnetic bias to said strip, said applied bias being along a predetermined direction in the plane of said magnetoresistive strip.
Claim 2
Dependent Claim
82 words
In a magnetic transducer having a thin film layer magnetoresistive strip in magnetic-coupling relationship with the magnetized data of a storage medium, a magnetically hard, permanently magnetized, thin film layer parallel to the plane of said magnetoresistive strip constantly magnetized in the same direction when exposed to Magnetic fields below a predetermined level, adjacent to said magnetoresistive strip for applying a permanent magnetic bias to said strip, said applied bias being along a predetermined direction in the plane of said magnetoresistive strip.
Claim 3
Dependent Claim
69 words
In a magnetic transducer having a thin film layer magnetoresistive strip in magnetic-coupling relationship with the magnetized data of a storage medium, an insulating layer on said strip and a magnetically hard permanently magnetized thin film layer parallel to the plane of said magnetoresistive strip on said insulating film for applying a permanent magnetic bias to said strip, said applied bias being along a magnetization axis of said strip.
Claim 4
Dependent Claim
69 words
In a magnetic transducer having a thin film layer magnetoresistive strip in magnetic-coupling relationship with the magnetized data of a storage medium, an insulating layer on said strip and a magnetically hard permanently magnetized thin film layer parallel to the plane of said magnetoresistive strip on said insulating film for applying a permanent magnetic bias to said strip, said applied bias being along a magnetization axis of said strip.
Claim 5
Dependent Claim
34 words
The invention of claim 2 wherein said magnetoresistive strip is of the order of 50-400A, said insulating layer of the order of 300-1000A and said magnetically hard film is of the order of 200-1000A.
Claim 6
Dependent Claim
59 words
In a magnetic transducer including a thin film layer magnetoresistive strip as the magnetic data sensing element of said transducer, a treated portion of said strip being selectively treated to be permanently magnetized, said treated portion of said sense strip being coplanar with said untreated portion and said treated portion serving as a biasing magnet for said untreated portion.
Claim 7
Dependent Claim
59 words
In a magnetic transducer including a thin film layer magnetoresistive strip as the magnetic data sensing element of said transducer, a treated portion of said strip being selectively treated to be permanently magnetized, said treated portion of said sense strip being coplanar with said untreated portion and said treated portion serving as a biasing magnet for said untreated portion.
Claim 8
Dependent Claim
31 words
In the transducer of claim 4 wherein said highly coercive treated portion of said strip applies a magnetic bias that is at right angles to the length of said magnetoresistive strip.
Claim 9
Dependent Claim
87 words
A magnetic transducer including a thin film magnetoresistive strip as the magnetic data sensing element of said transducer, a thin film electrically insulating layer on said strip, and a thin film highly coercive permanently magnetized magnetic layer on said insulating layer for applying a magnetic bias at any angle to the length of said strip, said highly coercive permanent magnetic layer being composed of coupled films wherein a soft magnetic layer is atomically coupled to a hard permanent magnetic layer so as to assume its high coercivity.
Claim 10
Dependent Claim
87 words
A magnetic transducer including a thin film magnetoresistive strip as the magnetic data sensing element of said transducer, a thin film electrically insulating layer on said strip, and a thin film highly coercive permanently magnetized magnetic layer on said insulating layer for applying a magnetic bias at any angle to the length of said strip, said highly coercive permanent magnetic layer being composed of coupled films wherein a soft magnetic layer is atomically coupled to a hard permanent magnetic layer so as to assume its high coercivity.
Claim 11
Dependent Claim
17 words
The transducer of claim 6 wherein said exchange coupled films consist of Ni-Fe deposited on Alpha Fe2O3.
Claim 12
Dependent Claim
17 words
The transducer of claim 6 wherein said exchange coupled films consist of Alpha Fe2O3 deposited on Ni-Fe.
Claim 13
Dependent Claim
15 words
The transducer of claim 6 wherein the hard film consists of Co deposited on vanadium.
Claim 14
Dependent Claim
15 words
The transducer of claim 6 wherein the hard film consists of Co deposited on chromium.
Claim 15
Dependent Claim
16 words
The transducer of claim 6 wherein said exchange coupled films consist of Ni-Co deposited on vanadium.
Claim 16
Dependent Claim
16 words
The transducer of claim 6 wherein said exchange coupled films consist of Ni-Co deposited on chromium.
Claim 17
Dependent Claim
14 words
The transducer of claim 7 wherein said exchange coupled films consist of binary Co-P.
Claim 18
Dependent Claim
78 words
In a transducer including a thin film magnetoresistive strip as the magnetic data sensing element of said transducer, two portions on opposite sides of an untreated portion of said magnetoresistive strip being treated to provide respective permanent magnetic coercivities much higher than the untreated portion of said strip, said highly coercive portions supplying a hard, permanent magnetic bias in a direction to said untreated sense strip, said two biasing magnetic portions and said untreated magnetoresistive strip being coplanar.
Claim 19
Dependent Claim
78 words
In a transducer including a thin film magnetoresistive strip as the magnetic data sensing element of said transducer, two portions on opposite sides of an untreated portion of said magnetoresistive strip being treated to provide respective permanent magnetic coercivities much higher than the untreated portion of said strip, said highly coercive portions supplying a hard, permanent magnetic bias in a direction to said untreated sense strip, said two biasing magnetic portions and said untreated magnetoresistive strip being coplanar.
Claim 20
Dependent Claim
109 words
In a transducer having a thin film sensing strip, said thin sensing strip being a magnetoresistive layer, and a hard, permanently magnetized thin film layer integral with said strip for applying magnetic bias to said strip, said permanently magnetized thin film layer being disposed relative to said strip such that a first vector perpendicular to the plane of said strip and a second vector perpendicular to the plane of said permanent magnet layer are substantially parallel and such that at least one edge of said permanent magnet layer is in close proximity with and substantially parallel to one edge of said strip for applying magnetic bias to said strip.
Claim 21
Dependent Claim
109 words
In a transducer having a thin film sensing strip, said thin sensing strip being a magnetoresistive layer, and a hard, permanently magnetized thin film layer integral with said strip for applying magnetic bias to said strip, said permanently magnetized thin film layer being disposed relative to said strip such that a first vector perpendicular to the plane of said strip and a second vector perpendicular to the plane of said permanent magnet layer are substantially parallel and such that at least one edge of said permanent magnet layer is in close proximity with and substantially parallel to one edge of said strip for applying magnetic bias to said strip.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |