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US5438470A Expired / Lapsed US ⏱️ 0.0 years remaining

Magnetoresistive structure with contiguous junction hard bias design with low lead resistance

Assignee: Western Digital Technologies Inc
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Filing: 1994-05-13
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Granted: 1995-08-01
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Expires: 2014-05-13
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Abstract

Abstract A magnetoresistive read transducer includes a magnetoresistive (MR) layer having end regions spaced by a central active regions. A pair of hard-magnetic layers provide the longitudinal magnetic bias to the magnetoresistive layer. Each of the hard-magnetic layers is disposed in contact with one of the end regions of the magnetoresistive layer. In addition, a pair of electrical leads provide the bias current to the magnetoresistive layer. Each of the electrical leads is also disposed in contact with one of the end regions of the magnetoresistive layer. This arrangement enable the transducer of the present invention with the most optimal design. In essence, electrical current directly passes through the central active region of the magnetoresistive layer via the electrical leads as a low electrical resistance path. Magnetic flux of the longitudinal bias directly passes through the central active region of the magnetoresistive layer with a reduced probability of magnetic discontinuity.

Inventors

  • 👤 Durga Ravipati
  • 👤 Yong Shen
  • 👤 William C. Cain

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-07 11:21
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/399

Claims Analysis

Total Claims: 17
Claim 1
Independent Claim 136 words
A thin-film magnetoresistive transducer comprising: a magnetoresistive layer formed of a ferromagnetic material, said magnetoresistive layer including end regions spaced by a central active region; first and second hard-magnetic layers, each of said hard-magnetic layers being disposed in abutting contact with one of said end regions of said magnetoresistive layer, said hard-magnetic layers cooperatively providing a magnetic bias to said magnetoresistive layer; and first and second electrical leads formed of an electrically conductive material, each of said electrical leads being disposed in contact respectively with one of said end regions of said magnetoresistive layer, such that said first and second electrical leads and said magnetoresistive layer form a direct electrical path of low lead resistances, said each one of said electrical leads forming abutting junctions with said magnetoresistive layer and one of said hard magnetic layers
Claim 2
Dependent Claim 136 words
A thin-film magnetoresistive transducer comprising: a magnetoresistive layer formed of a ferromagnetic material, said magnetoresistive layer including end regions spaced by a central active region; first and second hard-magnetic layers, each of said hard-magnetic layers being disposed in abutting contact with one of said end regions of said magnetoresistive layer, said hard-magnetic layers cooperatively providing a magnetic bias to said magnetoresistive layer; and first and second electrical leads formed of an electrically conductive material, each of said electrical leads being disposed in contact respectively with one of said end regions of said magnetoresistive layer, such that said first and second electrical leads and said magnetoresistive layer form a direct electrical path of low lead resistances, said each one of said electrical leads forming abutting junctions with said magnetoresistive layer and one of said hard magnetic layers
Claim 3
Dependent Claim 26 words
The thin-film magnetoresistive transducer as set forth in claim 1 wherein each of said electrical leads is disposed in contact with one of said hard-magnetic layers.
Claim 4
Dependent Claim 16 words
The thin-film magnetoresistive transducer as set forth in claim 1 wherein said magnetoresistive layer comprises Permalloy.
Claim 5
Dependent Claim 29 words
The thin-film magnetoresistive transducer as set forth in claim 1 wherein said first and second hard-magnetic layers comprise an alloy of cobalt, chromium and platinum on a chromium underlayer.
Claim 6
Dependent Claim 53 words
The thin-film magnetoresistive transducer as set forth in claim 1 wherein said magnetic bias is a longitudinal magnetic bias, and wherein said transducer further comprises a soft-magnetic layer disposed parallel to and separated from said magnetoresistive layer by a spacer layer, said soft-magnetic layer providing a transverse magnetic bias to said magnetoresistive layer.
Claim 7
Dependent Claim 28 words
The thin-film magnetoresistive transducer as set forth in claim 5 wherein said soft-magnetic layer comprises an alloy of nickel, iron and rhodium and said spacer layer comprises tantalum.
Claim 8
Dependent Claim 39 words
The thin-film magnetoresistive transducer as set forth in claim 6 wherein said magnetoresistive layer, said first and second hard-magnetic layers, said spacer layer and said soft-magnetic layer are disposed between two magnetic shields formed of a soft magnetic material.
Claim 9
Dependent Claim 207 words
A thin-film magnetoresistive transducer having low signal lead resistance and for converting changes in magnetic flux from a recording medium to electrical signals, comprising: a magnetoresistive layer formed of a ferromagnetic material, said magnetoresistive layer including end regions spaced by a central active region, said magnetoresistive layer varying in electrical resistivity in response to the changes in magnetic flux; first and second hard-magnetic layers, each of said hard-magnetic layers being disposed in abutting contact with one of said end regions of said magnetoresistive layer, said hard-magnetic layers cooperatively providing a longitudinal magnetic bias to said magnetoresistive layer; and first and second electrical leads formed of an electrically conductive material, each of said electrical leads being disposed in contact with one of said end regions of said magnetoresistive layer, such that when an electrical current passes through said magnetoresistive layer which varies in resistivity in response to the changes in magnetic flux intercepted by said transducer, a varying voltage is correspondingly generated at said magnetoresistive layer, the varying voltage corresponding to the electrical signals which directly pass through said electrical leads as the path of low lead resistance, each one of said electrical leads forming abutting junctions with said magnetoresistive layer and one of said hard magnetic layers
Claim 10
Dependent Claim 207 words
A thin-film magnetoresistive transducer having low signal lead resistance and for converting changes in magnetic flux from a recording medium to electrical signals, comprising: a magnetoresistive layer formed of a ferromagnetic material, said magnetoresistive layer including end regions spaced by a central active region, said magnetoresistive layer varying in electrical resistivity in response to the changes in magnetic flux; first and second hard-magnetic layers, each of said hard-magnetic layers being disposed in abutting contact with one of said end regions of said magnetoresistive layer, said hard-magnetic layers cooperatively providing a longitudinal magnetic bias to said magnetoresistive layer; and first and second electrical leads formed of an electrically conductive material, each of said electrical leads being disposed in contact with one of said end regions of said magnetoresistive layer, such that when an electrical current passes through said magnetoresistive layer which varies in resistivity in response to the changes in magnetic flux intercepted by said transducer, a varying voltage is correspondingly generated at said magnetoresistive layer, the varying voltage corresponding to the electrical signals which directly pass through said electrical leads as the path of low lead resistance, each one of said electrical leads forming abutting junctions with said magnetoresistive layer and one of said hard magnetic layers
Claim 11
Dependent Claim 40 words
The thin-film magnetoresistive transducer as set forth in claim 8 further comprising a soft-magnetic layer disposed parallel to and separated from said magnetoresistive layer by a spacer layer, said soft-magnetic layer providing a transverse magnetic bias to said magnetoresistive layer.
Claim 12
Dependent Claim 28 words
The thin-film magnetoresistive transducer as set forth in claim 9 wherein said soft-magnetic layer comprises an alloy of nickel, iron and rhodium and said spacer layer comprises tantalum.
Claim 13
Dependent Claim 26 words
The magnetoresistive read transducer as set forth in claim 10 wherein said hard-magnetic layers comprise an alloy of cobalt, chromium and platinum on a chromium underlayer.
Claim 14
Dependent Claim 28 words
The magnetoresistive read transducer as set forth in claim 11 wherein said electrical leads comprise gold on a thin layer of tantalum and said magnetoresistive layer comprises Permalloy.
Claim 15
Dependent Claim 39 words
The thin-film magnetoresistive transducer as set forth in claim 12 wherein said magnetoresistive layer, said first and second hard-magnetic layers, said spacer layer and said soft-magnetic layer are disposed between two magnetic shields formed of a soft magnetic material.
Claim 16
Dependent Claim 26 words
The magnetoresistive read transducer as set forth in claim 8 wherein said hard-magnetic layers comprise an alloy of cobalt, chromium and platinum on a chromium underlayer.
Claim 17
Dependent Claim 28 words
The magnetoresistive read transducer as set forth in claim 8 wherein said electrical leads comprise gold on a thin layer of tantalum and said magnetoresistive layer comprises Permalloy.

References Cited (Backward Citations)

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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) 1998-07-31 1999-01-30 1999-08-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2002-07-31 2003-01-30 2003-08-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2006-07-31 2007-01-30 2007-08-01 $7700.00 Window Closed / Lapsed

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