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公开(公告)号：JP2002304711A
公开(公告)日：2002-10-18
申请号：JP2001389357
申请日：2001-12-21
Applicant: IBM
Inventor： DILL FREDERICK HAYES , FONTANA JR ROBERT EDWARD , PARKIN STUART STEPHEN PAPWORTH , TSANG CHING HWA
Abstract: PROBLEM TO BE SOLVED: To provide an MR read head having an MTJ device formed to be sufficiently thin for attaining the high surface density by reducing the space between magnetic shields. SOLUTION: As to the magnetic tunnel junction MTJ device 100, the magneto-resistive(MR) read head has the MTJ device 100 located between two spaced-apart magnetic shields S1, S2. The magnetic shields function also as electrical leads for connecting the head to a detection circuit. Conductive spacer layers 102, 104 are located at the top and bottom of the MTJ device 100 to connect the MTJ device 100 to the shields. The thickness of the spacer layer is selected to optimize the spacing between the shields. Each of the shields has the pedestal region for reducing the electric short-circuit between the shields in the case the space between the shields is too small, and the MTJ device 100 is located between these two pedestals.
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公开(公告)号：JPH11213349A
公开(公告)日：1999-08-06
申请号：JP28899998
申请日：1998-10-12
Applicant: IBM
Inventor： FONTANA JR ROBERT E , PARKIN STUART STEPHEN PAPWORTH , TSANG CHING HWA
Abstract: PROBLEM TO BE SOLVED: To provide an MTJ(magnetic tunnel junction) MR(magneto-resistance) read head free from problems accompanying the existence of an edge part of an exposed MTJ layer on a detection surface. SOLUTION: The MTJ magneto-resistance read head for magnetic recording system is provided with an MTJ detection or free ferromagnetic layer 132 functioning as a magnetic flux guide which directs a magnetic flux from a magnetic recording medium to a tunnel junction. An MTJ fixed ferromagnetic layer 118 has a front edge part retreated from the detection surface of the head. The fixed ferromagnetic layer and the free ferromagnetic layer are brought into contact with opposite faces of an MTJ tunnel barrier layer 120, but the free ferromagnetic layer is extended beyond the rear edge part of one of the tunnel barrier layer and the fixed ferromagnetic layer which has the rear edge part nearer to the detection surface. The direction of magnetization of the fixed ferromagnetic layer is desirably fixed in the direction of an arrow 119 approximately perpendicular to the detection surface, namely, the magnetic recording medium by surface exchange coupling with an antiferromagnetic layer.
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公开(公告)号：JPH11213350A
公开(公告)日：1999-08-06
申请号：JP28901398
申请日：1998-10-12
Applicant: IBM
Inventor： FONTANA JR ROBERT E , PARKIN STUART STEPHEN PAPWORTH , TSANG CHING HWA , WILLIAMS MASON LAMAR
Abstract: PROBLEM TO BE SOLVED: To provide a magnetic tunnel junction magneto-resistance reading head for magnetic recording system which gives a large output signal. SOLUTION: The magneto-resistance read head is provided with an MTJ detection or free ferromagnetic layer 132 functioning as a magnetic flux guide which directs a magnetic flux from a magnetic recording medium to a tunnel junction 100, and an MTJ fixed ferromagnetic layer 118 and an MTJ tunnel barrier layer 120 are provided with front edge parts 206 and 210 which are approximately level with the detection surface of the head, and the fixed ferromagnetic layer 118 and the free ferromagnetic layer 132 are brought into contact with opposite faced of the MTJ tunnel barrier layer 120, and the free ferromagnetic layer 132 is extended beyond the rear edge part of one of the free ferromagnetic layer 132 and the tunnel barrier layer 118 which has the rear edge part 208 or 212 nearer to the detection surface, and it is secured that the magnetic flux is non-zero in the tunnel junction area. The direction of magnetization of the fixed ferromagnetic layer 118 is fixed in the direction perpendicular to the detection surface by surface exchange coupling with an antiferromagnetic layer 116. The direction of magnetization of the free ferromagnetic layer 132 is made parallel with the surface of a medium when an applied magnetic field is zero, and it is freely rotated when an applied magnetic field exists.
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公开(公告)号：JPH11213351A
公开(公告)日：1999-08-06
申请号：JP28902098
申请日：1998-10-12
Applicant: IBM
Inventor： DILL FREDERICK HAYES , FONTANA JR ROBERT E , PARKIN STUART STEPHEN PAPWORTH , TSANG CHING HWA
Abstract: PROBLEM TO BE SOLVED: To reduce the gap between magnetic shields to obtain a high surface density. SOLUTION: The magnetic shield enables a head to detect each magnetic transition from a magnetic recording medium without interference of adjacent transitions and functions as an electric lead which connects the head to a detection circuit. Conductive spacer layer 102 and 104 are arranged above and below an MTJ(magnetic tunnel junction) element to connect the MTJ element to the shield. The thickness of spacer layere 102 and 104 are selected so as to optimize the gap between shields. This thickness is a parameter which controls the linear resolution of data read from the magnetic recording medium. If the gap between shields is narrow, each shield has a pedestal area for the purpose of reducing a possibility of electric short-circuit between shields, and the MTJ element can be arranged between these two pedestals. In this case, the gap between shields on the outside of pedestals is larger than the inside of pedestal areas.
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公开(公告)号：DE69431149T2
公开(公告)日：2003-05-28
申请号：DE69431149
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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Patent Agency Ranking
公开(公告)号：DE69431149D1
公开(公告)日：2002-09-12
申请号：DE69431149
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：SG32343A1
公开(公告)日：1996-08-13
申请号：SG1995000354
申请日：1995-04-28
Applicant: IBM
Inventor： TSANG CHING HWA , FONTANA ROBERT EDWARD , LIN TSANN
IPC: G11B5/39
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公开(公告)号：AU5949386A
公开(公告)日：1987-02-19
申请号：AU5949386
申请日：1986-07-02
Applicant: IBM
Inventor： TSANG CHING HWA
Abstract: A magnetoresistive (MR) read transducer assembly comprises a thin film MR layer (10) which is longitudinally biased only in the end regions (12) by exchange bias developed by a thin film of antiferromagnetic material (16) that is deposited in direct contact with the MR layer in the end regions. The longitudinal bias is of a level sufficient to maintain the end regions of the MR layer in a single domain state and thereby induce a single domain state in the central region (14) of the MR layer. Transverse bias is produced within the central region of the MR layer of a level sufficient to maintain that region of the MR layer in a linear response mode. Spaced conductive elements (18,20) are connected to the MR layer within the central region to define a detection region so that sensing means connected to the conductive elements can determine the resistance changes in the detection region of the MR layer resulting from the magnetic fields intercepted by the MR layer.
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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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