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公开(公告)号：DE69420789D1
公开(公告)日：1999-10-28
申请号：DE69420789
申请日：1994-07-04
Applicant: IBM
Inventor： CHEN MAO-MIN , FONTANA ROBERT EDWARD , KROUNBI MOHAMAD TOWFIK , KUNG KENNETH TING-YUAN , LEE JAMES HSI-TANG , LO JYH-SHLIEY JERRY , TSANG CHING HWA , WANG PO-KANG
IPC: G11B5/39
Abstract: A magnetoresistive (MR) read transducer is disclosed having passive end regions separated by a central active region in which an MR layer is formed over substantially only the central active region and in which a magnetic bias layer is formed in each passive end region. In one embodiment, each of the magnetic bias layers includes a layer of ferromagnetic material and a layer of antiferromagnetic material overlaying and in contact with the ferromagnetic layer to provide an exchange-coupled magnetic bias field. Alternatively a hard magnetic material is used to form the biasing layer. Each of the magnetic bias layers form an abutting junction having magnetic and electrical continuity with the MR layer to produce a stable longitudinal magnetic bias field in the transducer, even when the length of the active region is small to accommodate small track widths.
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公开(公告)号：SG44410A1
公开(公告)日：1997-12-19
申请号：SG1996000218
申请日：1994-07-04
Applicant: IBM
Inventor： CHEN MAO-MIN , FONTANA ROBERT EDWARD , KROUNBI MOHAMAD TOWFIK , KUNG KENNETH TING-YUAN , LEE JAMES HSI-TANG , LO JYH-SHLIEY JERRY , TSANG CHING HWA , WANG PO-KANG
IPC: G11B5/39
Abstract: A magnetoresistive (MR) read transducer is disclosed having passive end regions separated by a central active region in which an MR layer is formed over substantially only the central active region and in which a magnetic bias layer is formed in each passive end region. In one embodiment, each of the magnetic bias layers includes a layer of ferromagnetic material and a layer of antiferromagnetic material overlaying and in contact with the ferromagnetic layer to provide an exchange-coupled magnetic bias field. Alternatively a hard magnetic material is used to form the biasing layer. Each of the magnetic bias layers form an abutting junction having magnetic and electrical continuity with the MR layer to produce a stable longitudinal magnetic bias field in the transducer, even when the length of the active region is small to accommodate small track widths.
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公开(公告)号：SG42849A1
公开(公告)日：1997-10-17
申请号：SG1996000132
申请日：1994-12-16
Applicant: IBM
Inventor： COFFEY KEVIN JOHN , FONTANA ROBERT EDWARD , HOWARD JAMES KENT , HYLTON TODD LANIER , PARKER MICHAEL ANDREW , TSANG CHING HWA
Abstract: A magnetoresistive read sensor incorporates a multilayer sensing element formed of one or more magnetoresistive elements in a planar array, each magnetoresistive element having a multilayer structure of at least two ferromagnetic layers separated by a nonmagnetic layer. The ferromagnetic layers are coupled antiferromagnetically by magnetostatic coupling at opposing edges of the ferromagnetic layers. A bias layer separated from the magnetoresistive sensing element by a spacer layer provides a magnetic field to bias the magnetoresistive sensing element at a desired non-signal point for linear response. The magnetoresistive sensing element is formed by alternatively depositing layers of ferromagnetic material and layers of nonmagnetic material on a substrate and then patterning the resulting structure using photolithographic techniques to provide a planar array of magnetoresistive elements. A conductive layer is deposited over the array filling in the spaces separating the magnetoresistive elements to provide electrical conductivity between the elements in the plane of the structure.
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公开(公告)号：DE69115070D1
公开(公告)日：1996-01-18
申请号：DE69115070
申请日：1991-02-04
Applicant: IBM
Inventor： FONTANA ROBERT EDWARD , HOULE FRANCES ANNE , TSANG CHING HWA
IPC: G01R33/09 , G11B5/39 , H01F10/32 , H01F41/22 , H01F41/30 , H01F41/34 , H01L43/12 , H01F41/14 , G01R33/06
Abstract: A method for producing a magnetic structure, such as a thin film magnetic head, in which the magnetic and electrical characteristics of magnetic material are tailored to produce magnetic and electrical characteristics in selected localized areas of the magnetic material. In an embodiment, the structure comprises a layer of magnetic material having an overlayer and an underlayer, and the magnetic characteristics of the material are modified by rapid thermal annealing.
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公开(公告)号：DE69534013D1
公开(公告)日：2005-03-24
申请号：DE69534013
申请日：1995-10-27
Applicant: IBM
Abstract: A magnetic field sensor (10) uses four individual magnetoresistive spin valve elements (A,B,C,D) electrically connected in a bridge circuit. The spin valve elements (A,B,C,D) are lithographically formed on the same substrate with their free layers (36) having their magnetization axes parallel to one another. An electrically conductive fixing layer is formed on the substrate but is insulated from the spin valve elements. The application of current through the fixing conductor during fabrication of the field sensor fixes the direction of magnetization of two of the pinned layers (39) to be antiparallel to the direction of magnetization of the other two pinned layers (39). The bridge circuit (10) output voltage is responsive to an external magnetic field (4) in the plane of the sensor (10). By appropriate fixing of the direction of magnetization of the pinned layers (39) during sensor (10) fabrication, and appropriate connection to the input (20,22) and output leads (24,26), the bridge circuit output voltage is a measure of either the magnetic field or field gradient.
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Patent Agency Ranking
公开(公告)号：AT289419T
公开(公告)日：2005-03-15
申请号：AT95116943
申请日：1995-10-27
Applicant: IBM
Abstract: A magnetic field sensor (10) uses four individual magnetoresistive spin valve elements (A,B,C,D) electrically connected in a bridge circuit. The spin valve elements (A,B,C,D) are lithographically formed on the same substrate with their free layers (36) having their magnetization axes parallel to one another. An electrically conductive fixing layer is formed on the substrate but is insulated from the spin valve elements. The application of current through the fixing conductor during fabrication of the field sensor fixes the direction of magnetization of two of the pinned layers (39) to be antiparallel to the direction of magnetization of the other two pinned layers (39). The bridge circuit (10) output voltage is responsive to an external magnetic field (4) in the plane of the sensor (10). By appropriate fixing of the direction of magnetization of the pinned layers (39) during sensor (10) fabrication, and appropriate connection to the input (20,22) and output leads (24,26), the bridge circuit output voltage is a measure of either the magnetic field or field gradient.
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公开(公告)号：AT221999T
公开(公告)日：2002-08-15
申请号：AT94119895
申请日：1994-12-16
Applicant: IBM
Inventor： COFFEY KEVIN ROBERT , FONTANA ROBERT EDWARD , HOWARD JAMES KENT , HYLTON TODD LANIER , PARKER MICHAEL ANDREW , TSANG CHING HWA
Abstract: A magnetoresistive read sensor incorporates a multilayer sensing element formed of one or more magnetoresistive elements in a planar array, each magnetoresistive element having a multilayer structure of at least two ferromagnetic layers separated by a nonmagnetic layer. The ferromagnetic layers are coupled antiferromagnetically by magnetostatic coupling at opposing edges of the ferromagnetic layers. A bias layer separated from the magnetoresistive sensing element by a spacer layer provides a magnetic field to bias the magnetoresistive sensing element at a desired non-signal point for linear response. The magnetoresistive sensing element is formed by alternatively depositing layers of ferromagnetic material and layers of nonmagnetic material on a substrate and then patterning the resulting structure using photolithographic techniques to provide a planar array of magnetoresistive elements. A conductive layer is deposited over the array filling in the spaces separating the magnetoresistive elements to provide electrical conductivity between the elements in the plane of the structure.
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公开(公告)号：DE69326308D1
公开(公告)日：1999-10-14
申请号：DE69326308
申请日：1993-11-15
Applicant: IBM
Inventor： CAIN WILLIAM CHARLES , DIENY BERNARD , FONTANA ROBERT EDWARD , SPERIOSU VIRGIL SIMON
Abstract: A magnetoresistive sensor based on the spin valve effect in which a component of the read element resistance varies as the cosine of the angle between the magnetization directions in two adjacent magnetic layers is described. The sensor read element includes two adjacent ferromagnetic layers separated by a non-magnetic metallic layer, the magnetic easy axis of each of the ferromagnetic layers being aligned along the longitudinal axis of the ferromagnetic layers and perpendicular to the trackwidth of an adjacent magnetic storage medium. The sense current flowing in the sensor element generates a bias field which sets the direction of magnetization in each ferromagnetic layer at an equal, but opposite, angle theta with respect to the magnetic easy axis thus providing an angular separation of 2 theta in the absence of an applied magnetic signal. The magnetizations of both ferromagnetic layers are responsive to an applied magnetic field to change their angular separation by an amount 2 delta theta .
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公开(公告)号：BR9504583A
公开(公告)日：1997-05-20
申请号：BR9504583
申请日：1995-10-27
Applicant: IBM
Inventor： DOVEK MORIS MUSA , FONTANA ROBERT EDWARD , SIMONE VIRGIL , SPONG JACQUELINE KETNER
Abstract: A magnetic field sensor (10) uses four individual magnetoresistive spin valve elements (A,B,C,D) electrically connected in a bridge circuit. The spin valve elements (A,B,C,D) are lithographically formed on the same substrate with their free layers (36) having their magnetization axes parallel to one another. An electrically conductive fixing layer is formed on the substrate but is insulated from the spin valve elements. The application of current through the fixing conductor during fabrication of the field sensor fixes the direction of magnetization of two of the pinned layers (39) to be antiparallel to the direction of magnetization of the other two pinned layers (39). The bridge circuit (10) output voltage is responsive to an external magnetic field (4) in the plane of the sensor (10). By appropriate fixing of the direction of magnetization of the pinned layers (39) during sensor (10) fabrication, and appropriate connection to the input (20,22) and output leads (24,26), the bridge circuit output voltage is a measure of either the magnetic field or field gradient.
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公开(公告)号：DE69204869T2
公开(公告)日：1996-05-02
申请号：DE69204869
申请日：1992-01-16
Applicant: IBM
Inventor： FONTANA ROBERT EDWARD , ROMANKIW LUBOMYR TARAS , WILLIAMS MASON LAMAR
Abstract: An integrated inductive write, magnetoresistive (MR) read thin film magnetic head comprising an open magnetic yoke having outside legs each having a winding thereon and a central leg having an opening across which the MR element is coupled. The outer legs are overlapped at one end to form confronting pole pieces having a transducing gap between the pole pieces, and the central leg is positioned between the pole pieces at one end and joined with the outer legs at the other end to form a symmetrical magnetic yoke structure. The windings are wound in a direction so that the flux produced by equally energizing the windings is equal and opposite in each of the outside legs, is additive at the transducing gap between the pole pieces, and produces no net flux through the central leg.
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