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公开(公告)号：JPH1091923A
公开(公告)日：1998-04-10
申请号：JP21464497
申请日：1997-08-08
Applicant: IBM
Inventor： GILL HARDAYAL SINGH , GURNEY BRUCE A , SMYTH JOSEPH FRANCIS , SPERIOSU VIRGIL SIMON , WERNER DOUGLAS JOHNSON
Abstract: PROBLEM TO BE SOLVED: To provide an orthogonal spin valve reading head having a spin valve sensor. SOLUTION: Spin valve sensors are arranged between a first and a second shield layers S1, S2 asymmetrically, when a detecting current is made to flow, a restriction magnetic fields by an anti-ferroelectric layer 74, a pin holding layer 72 and a spacer layer 76 partially or completely canceled by an induction magnetic field generated by a current induced in both shield layers when a detecting current is made to flow. The distance between a sensor and the second shield layer S2 is enlarged by providing an intermediate gap layer MG between spin valve sensors and the second shield layer S2.
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公开(公告)号：DE69132027D1
公开(公告)日：2000-04-13
申请号：DE69132027
申请日：1991-12-09
Applicant: IBM
Inventor： DIENY BERNARD , GURNEY BRUCE ALVIN , LAMBERT STEVEN EUGENE , MAURI DANIELE , PARKIN STUART STEPHEN PAPWORTH , SPERIOSU VIRGIL SIMON , WILHOIT DENNIS RICHARD
Abstract: A magnetoresistive (MR) sensor is disclosed which comprises a first and a second thin film layer of a magnetic material separated by a thin film layer of a non-magnetic metallic material. The first ferromagnetic layer is magnetically soft. The magnetization direction of the first layer of magnetic material is set substantially perpendicular to the magnetization of the second layer of magnetic material at zero applied field, and the magnetization direction of the second layer of magnetic material is fixed. A current flow is produced through the MR sensor, and the variations in voltage across the MR sensor are sensed due to changes in resistance of the MR sensor produced by rotation of the magnetization in the first layer of magnetic material as a function of the magnetic field being sensed. The variation of the resistance with the angle between the magnetizations of the first and second layers of magnetic material has been defined as the spin valve (SV) effect. It is also shown that, by a suitable direction of the current with respect to the fixed magnetization, the (SV) magnetoresistance can be added constructively to the usual anisotropic magnetoresistance.
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公开(公告)号：AU1788295A
公开(公告)日：1996-05-09
申请号：AU1788295
申请日：1995-05-04
Applicant: IBM
Inventor： DOVEK MORIS MUSA , FONTANA ROBERT EDWARD JR , SPERIOSU VIRGIL SIMON , SPONG JAQUELIN 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：DE69430964D1
公开(公告)日：2002-08-22
申请号：DE69430964
申请日：1994-01-11
Applicant: IBM
Inventor： GURNEY BRUCE ALVIN , HEIM DAVID EUGENE , LEFAKIS HARALAMBOS , NEED III OMAR U , SPERIOSU VIRGIL SIMON , WILHOIT DENNIS RICHARD
Abstract: A magnetoresistive read sensor based on the spin valve effect is described, 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. The sensor read element includes two adjacent ferromagnetic layers separated by a nonmagnetic metallic layer. A layer of nonmagnetic electrically conductive material is deposited adjacent to and in contact with at least one of the ferromagnetic layers (referred to as a filter layer) to form a back or conduction layer which provides a low resistance path for conduction electrons transmitted through the adjacent filter layer. The thickness of the filter layer is selected such that it effectively blocks conduction electrons having spins antiparallel to the direction of magnetization in the filter layer while allowing conduction electrons with parallel spins to be transmitted through the layer into the adjacent back layer. The magnetization of the filter layer is free to rotate in response to an applied magnetic field thereby effectively varying the electrically resistance to conduction electrons in the back/filter layer. The thickness of the back layer is selected to optimize the sensor parameters being measured and is in a range of about 4.0A to 1000A.
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公开(公告)号：SG44357A1
公开(公告)日：1997-12-19
申请号：SG1995002207
申请日：1993-08-12
Applicant: IBM
Inventor： BAUMGART PETER MICHAEL , DIENY BERNARD , GURNEY BRUCE ALVIN , SPERIOSU VIRGIL SIMON , WILHOIT DENNIS RICHARD
Abstract: A magnetoresistive read 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 nonmagnetic metallic layer. A layer of antiferromagnetic material is formed over one of the ferromagnetic layers to provide an exchange bias field which fixes or "pins" the magnetization direction in the one ferromagnetic layer. An interlayer of magnetically soft material is deposited between the ferromagnetic and antiferromagnetic layers separating the ferromagnetic layer from the antiferromagnetic layer and enhancing the exchange coupling, particularly in the instance where the ferromagnetic material is iron or an iron alloy.
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Patent Agency Ranking
公开(公告)号：SG42305A1
公开(公告)日：1997-08-15
申请号：SG1996000086
申请日：1991-12-09
Applicant: IBM
Inventor： DIENY BERNARD , GURNEY BRUCE ALVIN , LAMBERT STEVEN EUGENE , MAURI DANIELE , PARKIN STUART STEPHEN PAPWORTH , SPERIOSU VIRGIL SIMON , WILHOIT DENNIS RICHARD
Abstract: A magnetoresistive (MR) sensor is disclosed which comprises a first and a second thin film layer of a magnetic material separated by a thin film layer of a non-magnetic metallic material. The first ferromagnetic layer is magnetically soft. The magnetization direction of the first layer of magnetic material is set substantially perpendicular to the magnetization of the second layer of magnetic material at zero applied field, and the magnetization direction of the second layer of magnetic material is fixed. A current flow is produced through the MR sensor, and the variations in voltage across the MR sensor are sensed due to changes in resistance of the MR sensor produced by rotation of the magnetization in the first layer of magnetic material as a function of the magnetic field being sensed. The variation of the resistance with the angle between the magnetizations of the first and second layers of magnetic material has been defined as the spin valve (SV) effect. It is also shown that, by a suitable direction of the current with respect to the fixed magnetization, the (SV) magnetoresistance can be added constructively to the usual anisotropic magnetoresistance.
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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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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：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：SG46731A1
公开(公告)日：1998-02-20
申请号：SG1996009674
申请日：1996-05-02
Applicant: IBM
Inventor： FONTANA ROBERT EDWARD JR , GURNEY BRUCE ALVIN , LIN TSANN , SPERIOSU VIRGIL SIMON , TSANG CHING HWA , WILHOIT DENNIS RICHARD
Abstract: A spin valve magnetoresistive (SVMR) sensor uses a laminated antiparallel (AP) pinned layer 70 in combination with an improved antiferromagnetic (AF) exchange biasing layer 57. The pinned layer comprises two ferromagnetic films 72, 74 separated by a nonmagnetic coupling film 73 such that the magnetizations of the two ferromagnetic films are strongly coupled together antiferromagnetically in an antiparallel orientation. This laminated AP pinned layer is magnetically rigid in the small field excitations required to rotate the SVMR sensor's free layer. When the magnetic moments of the two ferromagnetic layers in this AP pinned layer are nearly the same, the net magnetic moment of the pinned layer is small. However, the exchange field is correspondingly large because it is inversely proportional to the net magnetic moment. The laminated AP pinned layer has its magnetization fixed or pinned by an AF material that is highly corrosion resistant but that has an exchange anisotropy too low to be usable in conventional SVMR sensors. In the preferred embodiment the AF layer is nickel-oxide and is formed on one of the magnetoresistive (MR) shields that serves as the substrate 45. Thus the AF material also serves as the insulating MR gap material. The location of the AF layer and the laminated AP-pinned layer to which it is exchange coupled on the bottom of the SVMR sensor allows for improved longitudinal biasing of the free layer when the SVMR sensor is fabricated.
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