EP0558237A2
Expired / Lapsed
EP
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Magnetoresistive read transducer having improved bias profile
Assignee: International Business Machines Corp
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Filing: 1993-02-18
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Granted: —
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Expires: 2013-02-18
Abstract
Abstract A magnetoresistive (MR) read transducer having passive end regions (28, 38) separated by a central active region (25, 34) comprises an MR layer (27, 31) made from a material having a low uniaxial magnetic anisotropy. A soft magnetic bias layer (24, 33) is adjacent to but spaced from the MR layer in the central region (25, 34) only, and the soft magnetic bias layer (24, 33) is made from a material having a high uniaxial magnetic anisotropy. A longitudinal bias is produced directly in each of the end regions (28, 38) only, and the means for producing the longitudinal bias comprises a layer (26) made from a material having a high uniaxial magnetic anisotropy. Control of the uniaxial anisotropy can be achieved by choosing materials of appropriate magnetostriction or intrinsic uniaxial anisotropy.
Inventors
- 👤 Mao-Min Chen
- 👤 Kochan Ju
- 👤 Mohamad T. Krounbi
- 👤 Ching Hwa Tsang
- 👤 Po-Kang Wang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 21:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
109 words
A magnetoresistive read transducer having passive end regions (28, 38) separated by a central active region (25, 34) comprising: a magnetoresistive layer (22, 31) having a sensing edge extending over at least said central active region; and a soft magnetic bias layer (24, 33) in said central active region, adjacent but spaced from said magnetoresistive layer, characterised in that said magnetoresistive layer (22, 31) is made from a material having a relatively low magnetic anisotropy, whereas said soft magnetic bias layer is made from a material having a magnetic anisotropy in a direction transverse to said sensing edge which is high relative to the material of said magnetoresistive layer.
Claim 2
Dependent Claim
18 words
A magnetoresistive read transducer according to claim 1 wherein said magnetoresistive layer extends over said central region only.
Claim 3
Dependent Claim
39 words
A magnetoresistive read transducer according to claim 1 or claim 2 wherein said soft magnetic bias layer (24, 33) comprises a ternary alloy NiFeX where X is taken from the group consisting of Rh, Ti, Cr, Ir and Nb
Claim 4
Dependent Claim
24 words
A magnetoresistive read transducer according to claim 1 or claim 2 wherein said soft magnetic bias layer (24, 33) comprises a cobalt based material.
Claim 5
Dependent Claim
72 words
A magnetoresistive read transducer according to any one of the preceding claims further comprising means for producing a longitudinal magnetic bias directly in and substantially only in each of said end regions (28, 38), said means for producing a longitudinal bias comprising a layer (26) made from a material having a magnetic anisotropy along the longitudinal direction of the sensing edge which is high relative to the material of the magnetoresistive layer.
Claim 6
Dependent Claim
77 words
A magnetoresistive read transducer according to claim 5 wherein the material of said magnetoresistive layer (22, 31) has a relatively low magnetostriction coefficient; the material of said soft magnetic bias layer (24, 33) has a positive magnetostriction coefficient which is high relative to the material of the magnetoresistive layer; and the material of said layer (26) for producing a longitudinal bias has a negative magnetostriction coefficient which is high relative to the material of the magnetoresistive layer.
Claim 7
Dependent Claim
46 words
A magnetoresistive read transducer according to any one of the preceding claims wherein said magnetoresistive layer (22, 31) has a magnetostriction coefficient of 1 x 10⁻⁶ or less and said soft magnetic bias layer (24, 33) has a magnetostriction coefficient of 5 x 10⁻⁶ or greater.
Claim 8
Dependent Claim
34 words
A magnetoresistive read transducer according to any one of claims 5 to 7 wherein said layer (26) comprising means for producing a longitudinal bias has a magnetostriction coefficient of -15 x 10⁻⁶ or greater.
Claim 9
Dependent Claim
56 words
A magnetoresistive read transducer according to any one of claims 5 to 8 wherein said means for producing a longitudinal bias comprises an antiferromagnetic material (36) in contact with a ferromagnetic material (35) to produce an exchange bias field of a level sufficient to maintain said end regions of said transducer in a single domain state.
Claim 10
Dependent Claim
26 words
A magnetoresistive read transducer according to any one of claims 5 to 8 wherein said means for producing a longitudinal bias comprises a hard magnetic layer.
Claim 11
Dependent Claim
27 words
A magnetoresistive read transducer according to any one of claims 5 to 8 wherein said means for producing a longitudinal bias comprises a layer of ferromagnetic material.
Claim 12
Dependent Claim
21 words
A magnetoresistive read transducer according to claim 11 wherein said layer of ferromagnetic material is subjected to a thermal oxidation treatment.
References Cited (Backward Citations)
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