Patent US5532892A successfully refreshed from Google Patents.
US5532892A
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US
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Soft adjacent layer biased magnetoresistive device incorporating a natural flux closure design utilizing coplanar permanent magnet thin film stabilization
Assignee: PHC Corp
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Filing: 1995-06-05
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Granted: 1996-07-02
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Expires: 2015-06-05
Abstract
Abstract A soft adjacent layer biased magnetoresistive ("MR") device, and a method for producing the same, which incorporates a natural flux closure design utilizing coplanar thin film permanent magnets to stabilize the device while obviating induced domain walls in the magnetoresistive and soft adjacent layers ("SAL"). The device structure includes an SAL film and overlying magnetic spacer layer ("MSL") in conjunction with an MR film to produce an SAL biased magnetoresistive structure ("MRS") with the MR layer patterned to a shortened length with respect to the SAL and MSL layers. A non-magnetic metal or dielectric separation layer of on the order of 20-300 angstroms ("Å") is then deposited over the MSL layer and the sides of the MR layer followed by the deposition of permanent magnet layer portions substantially coplanar with the MR layer to produce a low energy equilibria device with high sensitivity and superior signal output.
Inventors
- 👤 J. Lamar Nix
- 👤 Guy F. Ruse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3929; G11B5/3935; G11B5/398; G11B5/399; G11B5/3967
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
78 words
A magnetoresistive device comprising: a magnetoresistive layer presenting first and second oppositely disposed end portions transverse to a major axis thereof, said magnetoresistive layer in an overlying relationship with respect to a soft adjacent layer; and first and second permanent magnet layer portions in an overlying relationship with respect to said soft adjacent layer and disposed adjacent to, but spaced apart from, said first and second end portions of said magnetoresistive layer in a generally coplanar relationship thereto.
Claim 2
Dependent Claim
78 words
A magnetoresistive device comprising: a magnetoresistive layer presenting first and second oppositely disposed end portions transverse to a major axis thereof, said magnetoresistive layer in an overlying relationship with respect to a soft adjacent layer; and first and second permanent magnet layer portions in an overlying relationship with respect to said soft adjacent layer and disposed adjacent to, but spaced apart from, said first and second end portions of said magnetoresistive layer in a generally coplanar relationship thereto.
Claim 3
Dependent Claim
39 words
The device of claim 1 further comprising a spacer layer interposed between said magnetoresistive layer and said soft adjacent layer, said spacer layer being generally coextensive with said soft adjacent layer and in an overlying relationship with respect thereto.
Claim 4
Dependent Claim
20 words
The device of claim 2 wherein said spacer layer is selected from a group consisting essentially of Ta or Ti.
Claim 5
Dependent Claim
11 words
The device of claim 1 wherein said magnetoresistive layer comprises NiFe.
Claim 6
Dependent Claim
22 words
The device of claim 1 wherein said soft adjacent layer is selected from a group consisting essentially of NiFeMo, NiFeCr or NiFeTa.
Claim 7
Dependent Claim
18 words
The device of claim 1 further comprising first and second electrodes for providing electrical contact to said device.
Claim 8
Dependent Claim
20 words
The device of claim 6 wherein said first and second electrodes are selected from a group consisting essentially of Au.
Claim 9
Dependent Claim
15 words
The device of claim 6 wherein said first and second electrodes contact said magnetoresistive layer.
Claim 10
Dependent Claim
21 words
The device of claim 6 wherein said first and second electrodes contact said first and second permanent magnet layer portions respectively.
Claim 11
Dependent Claim
32 words
The device of claim 1 wherein separation between said first and second permanent magnet layer portions and said first and second end portions of said magnetoresistive layer is substantially between 20-300 angstroms.
Claim 12
Dependent Claim
22 words
The device of claim 1 wherein said first and second end portions of said magnetoresistive layer are orthogonal to said major axis.
Claim 13
Dependent Claim
34 words
The device of claim 1 wherein said first and second end portions of said magnetoresistive layer are generally defined by an ellipse having its foci generally along said major axis of said magnetoresistive layer.
Claim 14
Dependent Claim
24 words
The device of claim 12 wherein said ellipse presents a dimension along said major axis substantially 1.1 to 1.5 times the desired magnetic trackwidth.
Claim 15
Dependent Claim
26 words
The device of claim 12 wherein said ellipse presents a dimension transverse to said major axis substantially 1.1 to 1.5 times the desired magnetoresistive stripe height.
Claim 16
Dependent Claim
28 words
The device of claim 1 wherein said first and second end portions of said magnetoresistive layer are curvilinearly disposed within a plane generally defined by said magnetoresistive layer.
Claim 17
Dependent Claim
22 words
The device of claim 1 wherein said first and second end portions of said magnetoresistive layer are non-orthogonal to said major axis.
Claim 18
Dependent Claim
34 words
The device of claim 1 wherein separation between said first and second permanent magnet layer portions and said first and second end portions of said magnetoresistive layer is defined by a non-magnetic metal layer.
Claim 19
Dependent Claim
19 words
The device of claim 17 wherein said non-magnetic metal layer is selected from a group consisting essentially of Cr.
Claim 20
Dependent Claim
33 words
The device of claim 1 wherein separation between said first and second permanent magnet layer portions and said first and second end portions of said magnetoresistive layer is defined by a dielectric layer.
Claim 21
Dependent Claim
22 words
The device of claim 19 wherein said dielectric layer is selected from a group consisting essentially of Al 2 O 3 .
Claim 22
Dependent Claim
23 words
The device of claim 1 wherein said permanent magnet layer portions are selected from a group consisting essentially of CoPt, CoPtTa or CoPtCr.
Claim 23
Dependent Claim
66 words
A magnetoresistive device comprising: a magnetoresistive layer; a soft adjacent layer disposed in an underlying relationship with respect to said magnetoresistive layer; and first and second permanent magnet layer portions adjacent to, but separated apart from said magnetoresistive layer, said first and second permanent magnet layer portions being generally coplanar with said magnetoresistive layer and in an overlying relationship with respect to said soft adjacent layer.
Claim 24
Dependent Claim
66 words
A magnetoresistive device comprising: a magnetoresistive layer; a soft adjacent layer disposed in an underlying relationship with respect to said magnetoresistive layer; and first and second permanent magnet layer portions adjacent to, but separated apart from said magnetoresistive layer, said first and second permanent magnet layer portions being generally coplanar with said magnetoresistive layer and in an overlying relationship with respect to said soft adjacent layer.
Claim 25
Dependent Claim
32 words
The magnetoresistive device of claim 22 further comprising a spacer layer interposed between said magnetoresistive layer and said soft adjacent layer, said spacer layer being generally coextensive with said soft adjacent layer.
Claim 26
Dependent Claim
26 words
The device of claim 22 comprising a separation between said first and second permanent magnet layer portions and said magnetoresistive layer of substantially between 0-300 angstroms.
Claim 27
Dependent Claim
14 words
The device of claim 24 wherein said separation is defined by a non-magnetic metal.
Claim 28
Dependent Claim
18 words
The device of claim 24 wherein said non-magnetic metal is selected from a group consisting essentially of Cr.
Claim 29
Dependent Claim
14 words
The device of claim 24 wherein said separation is defined by a dielectric material.
Claim 30
Dependent Claim
22 words
The device of claim 27 wherein said dielectric material is selected from a group consisting essentially of Al 2 O 3 .
Claim 31
Dependent Claim
11 words
The device of claim 22 wherein said magnetoresistive layer comprises NiFe.
Claim 32
Dependent Claim
22 words
The device of claim 22 wherein said soft adjacent layer is selected from a group consisting essentially of NiFeMo, NiFeCr or NiFeTa.
Claim 33
Dependent Claim
20 words
The device of claim 27 wherein said spacer layer is selected from a group consisting essentially of Ta or Ti.
Claim 34
Dependent Claim
23 words
The device of claim 22 wherein said permanent magnet layer portions are selected from a group consisting essentially of CoPt, CoPtTa or CoPtCr.
Claim 35
Dependent Claim
18 words
The device of claim 22 further comprising first and second electrodes for providing electrical contact to said device.
Claim 36
Dependent Claim
20 words
The device of claim 33 wherein said first and second electrodes are selected from a group consisting essentially of Au.
Claim 37
Dependent Claim
15 words
The device of claim 33 wherein said first and second electrodes contact said magnetoresistive layer.
Claim 38
Dependent Claim
21 words
The device of claim 33 wherein said first and second electrodes contact said first and second permanent magnet layer portions respectively.
Claim 39
Dependent Claim
27 words
The device of claim 22 wherein first and second end portions of said magnetoresistive layer transverse to a major axis thereof are orthogonal to said major axis.
Claim 40
Dependent Claim
34 words
The device of claim 22 wherein first and second end portions of said magnetoresistive layer are generally defined by an ellipse having its foci generally lying along a major axis of said magnetoresistive layer.
Claim 41
Dependent Claim
24 words
The device of claim 38 wherein said ellipse presents a dimension along said major axis substantially 1.1 to 1.5 times the desired magnetic trackwidth.
Claim 42
Dependent Claim
26 words
The device of claim 38 wherein said ellipse presents a dimension transverse to said major axis substantially 1.1 to 1.5 times the desired magnetoresistive stripe height.
Claim 43
Dependent Claim
27 words
The device of claim 22 wherein first and second end portions of said magnetoresistive layer are curvilinearly disposed within a plane generally defined by said magnetoresistive layer.
Claim 44
Dependent Claim
28 words
The device of claim 22 wherein said first and second end portions of said magnetoresistive layer transverse to a major axis thereof are non-orthogonal to said major axis.
Claim 45
Dependent Claim
74 words
A magnetoresistive device comprising: a magnetoresistive layer; a soft adjacent layer in an underlying relationship with respect to said magnetoresistive layer; a separation layer adjoining opposing end portions of said magnetoresistive layer; and first and second permanent magnet regions contiguous with said separation layer and generally coplanar with said magnetoresistive layer at said end portions of said magnetoresistive layer whereby said first and second permanent magnet regions provide longitudinal bias to said magnetoresistive layer.
Claim 46
Dependent Claim
74 words
A magnetoresistive device comprising: a magnetoresistive layer; a soft adjacent layer in an underlying relationship with respect to said magnetoresistive layer; a separation layer adjoining opposing end portions of said magnetoresistive layer; and first and second permanent magnet regions contiguous with said separation layer and generally coplanar with said magnetoresistive layer at said end portions of said magnetoresistive layer whereby said first and second permanent magnet regions provide longitudinal bias to said magnetoresistive layer.
Claim 47
Dependent Claim
11 words
The device of claim 43 wherein said magnetoresistive layer comprises NiFe.
Claim 48
Dependent Claim
33 words
The device of claim 43 further comprising a magnetic spacer layer interposed between said magnetoresistive layer and said soft magnetic layer. said magnetic spacer layer being generally coextensive with said soft magnetic layer.
Claim 49
Dependent Claim
14 words
The device of claim 43 wherein said magnetoresistive layer is substantially elliptical in configuration.
Claim 50
Dependent Claim
13 words
The device of claim 43 wherein said separation layer comprises a non-magnetic metal.
Claim 51
Dependent Claim
18 words
The device of claim 47 wherein said non-magnetic metal is selected from a group consisting essentially of Cr.
Claim 52
Dependent Claim
13 words
The device of claim 43 wherein said separation layer comprises a dielectric material.
Claim 53
Dependent Claim
22 words
The device of claim 43 wherein said dielectric material is selected from a group consisting2 essentially of Al 2 O 3 .
Claim 54
Dependent Claim
24 words
The device of claim 43 wherein said first and second magnetic regions are selected from a group consisting essentially of CoPt, CoPtTa or CoPtCr.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-02 | 2000-01-01 | 2000-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-02 | 2004-01-01 | 2004-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-02 | 2008-01-01 | 2008-07-02 | $7700.00 | Window Closed / Lapsed |