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公开(公告)号：JPH0855312A
公开(公告)日：1996-02-27
申请号：JP10632294
申请日：1994-04-22
Applicant: IBM
Inventor： CAIN WILLIAM CHARLES , HEIM DAVID E , WANG PO-KANG
Abstract: PURPOSE: To obtain a constant field generated by ferromagnetic exchange coupling and a current and thus enable appropriate offset of influence thereof, by additionally providing a magnetic flux keeper layer and a spacer layer in a spin valve structure. CONSTITUTION: A magnetoresistive sensor 20 has a layered spin valve structure, including first and second thin layers 28, 34 of a ferromagnetic material and separated from each other by a spacer layer 32 of a non-magnetic metal. With a zero-application magnetic field, the direction of magnetization of the first layer 28 is caused to be in parallel to the longitudinal axis of the sensor 20 and perpendicular to the fixed direction of magnetization of the second layer 34. In addition, a thin magnetic flux keeper layer 24 is provided which is separated by the spacer layer 32 and has a fixed direction of magnetization opposite to the direction of magnetization of the second layer 34 and a product of thickness of the substantially same moment as the second layer to offset a static magnetic field from the second layer 34. A power source 48 causes a current to flow via the sensor 20 so as to generate a magnetic field offsetting ferromagnetic exchange coupling between the first and second layers 28, 34. Detection means 50 detects fluctuations in the resistance of the sensor 20 due to the difference in the rotation of magnetic fields of the first and second layers 28, 34.
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公开(公告)号：MY121197A
公开(公告)日：2006-01-28
申请号：MYPI9401782
申请日：1994-07-08
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 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 LAYERS IS FORMED IN EACH PASSIVE END REGION. 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. EACH OF THE MAGNETIC BIAS LAYERS FORM AN ABUTTING JUNCTION HAVING MAGNETIC AND ELECTRICALLY CONTINUITY WITH THE MR LAYER TO PRODUCE A LONGITUDINAL MAGNETIC BIAS FIELD IN THE TRANSDUCER. FIG 2
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公开(公告)号：DE69420789T2
公开(公告)日：2000-04-27
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：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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Patent Agency Ranking
公开(公告)号：SG44404A1
公开(公告)日：1997-12-19
申请号：SG1996000193
申请日：1993-02-18
Applicant: IBM
Inventor： CHEN MAO-MIN , JU KOCHAN , KROUNBI MOHAMAD T , TSANG CHING HWA , WANG PO-KANG
IPC: G11B5/39
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.
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公开(公告)号：HK71696A
公开(公告)日：1996-05-03
申请号：HK71696
申请日：1996-04-25
Applicant: IBM
Inventor： BEST JOHN STEWART , WANG PO-KANG
Abstract: A method of positioning separate read and write heads in a disk file compensates for misalignment of the heads when reading and writing data on the disk. Two sets of servo information are generated for each track on the disk. These sets are radially displaced with respect to each other by a distance equal to the respective misalignments between the read and write heads at each respective track. One set is generated by the write head. The other set is generated by the write head while the read head is aligned with said one set. Thereafter, to write data on a selected track, the read head is first aligned with said one set of servo information and then data is written on said track with the write head. To read data on a selected track, the read head is aligned to said other set of servo information and then the data is read by said read head.
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公开(公告)号：SG44674A1
公开(公告)日：1997-12-19
申请号：SG1996005392
申请日：1994-04-26
Applicant: IBM
Inventor： CAIN WILLIAM CHARLES , HEIM DAVID EUGENE , WANG PO-KANG
Abstract: A magnetoresistive (MR) sensing system comprises an MR sensor 20 with a layered spin valve structure including thin first 28 and second 34, 38 layers of ferromagnetic material separated by a thin layer 32 of nonmagnetic metallic material. The magnetization direction of the first layer at a zero applied magnetic field is substantially parallel to the longitudinal dimension of the MR sensor and substantially perpendicular to the fixed or "pinned" magnetization direction of the second layer. A thin keeper layer 24 of ferromagnetic material is separated by a thin spacer layer 26 from the layered spin valve structure. This keeper layer has a fixed magnetization direction substantially opposite that of the second layer and a moment-thickness product substantially equal to that of the second layer for cancelling the magnetostatic field from the second layer. A current flow is produced through the MR sensor to produce a magnetic field of a sign and magnitude which cancels the ferromagnetic exchange coupling between the first and second layers. Variations in resistivity of the MR sensor due to difference in rotation of the magnetizations in the first and second layers are sensed as a function of the magnetic field being sensed.
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公开(公告)号：DE69021315T2
公开(公告)日：1996-04-25
申请号：DE69021315
申请日：1990-09-28
Applicant: IBM
Inventor： KROUNBI MOHAMAD TOWFIK , VOEGELI OTTO , WANG PO-KANG
IPC: G11B5/39
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公开(公告)号：DE68923539T2
公开(公告)日：1996-02-29
申请号：DE68923539
申请日：1989-12-18
Applicant: IBM
Inventor： KROUNBI MOHAMAD TOWFIK , VOEGELI OTTO , WANG PO-KANG
IPC: G11B5/39
Abstract: A magnetoresistive (MR) read transducer comprising an MR layer (11) having passive end regions (14) separated by a central active region (12). A longitudinal bias is produced by a thin film (16) of hard magnetic material in the end regions only, and the thin film of hard magnetic material is spaced from the MR layer by a nonmagnetic spacer layer (18) so that a magnetostatic longitudinal bias is produced of a level to maintain the passive end regions of the MR layer in a stable state.
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