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公开(公告)号：DE69534314T2
公开(公告)日：2006-04-20
申请号：DE69534314
申请日：1995-05-02
Applicant: IBM
Inventor： COFFEY KEVIN ROBERT , GURNEY BRUCE ALVIN , HEIM DAVID EUGENE , LEFAKIS HARALAMBOS , MAURI DANIELE , SPERIOSU VIRGIL SIMON , WILHOIT DENNIS RICHARD
Abstract: An SVMR sensor (60) having a self-pinned laminated layer (70) with at least two ferromagnetic films (72,74) antiferromagnetically coupled to one another across a thin antiferromagnetically (AF) coupling film (73). Since the two ferromagnetic films (72,74) in this laminated layer (70) have their magnetic moments aligned antiparallel, their two magnetic moments can be made to essentially cancel by making the two ferromagnetic films (72,74) of substantially the same thickness. The magnetic field energy generated by the signal field acting on this laminated layer (70) will be significantly less than the effective anisotropy energy of the laminated layer (70). As a result, the laminated layer (70) will not rotate in the presence of the signal field, but will be "self-pinned". A hard-bias or exchange bias layer in not needed, also eliminating the need for Ni-Mn and its associated high-temperature process.
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公开(公告)号：DE69430964T2
公开(公告)日：2003-02-13
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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3.发明专利
公开(公告)号：SG42851A1
公开(公告)日：1997-10-17
申请号：SG1996000141
申请日：1994-01-11
Applicant: IBM
Inventor： GURNEY BRUCE ALVIN , HEIM DAVID EUGENE , LEFAKIS HARALAMBOS , NEED OMAR U III , 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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Patent Agency Ranking
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：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：DE69534314D1
公开(公告)日：2005-08-25
申请号：DE69534314
申请日：1995-05-02
Applicant: IBM
Inventor： COFFEY KEVIN ROBERT , GURNEY BRUCE ALVIN , HEIM DAVID EUGENE , LEFAKIS HARALAMBOS , MAURI DANIELE , SPERIOSU VIRGIL SIMON , WILHOIT DENNIS RICHARD
Abstract: An SVMR sensor (60) having a self-pinned laminated layer (70) with at least two ferromagnetic films (72,74) antiferromagnetically coupled to one another across a thin antiferromagnetically (AF) coupling film (73). Since the two ferromagnetic films (72,74) in this laminated layer (70) have their magnetic moments aligned antiparallel, their two magnetic moments can be made to essentially cancel by making the two ferromagnetic films (72,74) of substantially the same thickness. The magnetic field energy generated by the signal field acting on this laminated layer (70) will be significantly less than the effective anisotropy energy of the laminated layer (70). As a result, the laminated layer (70) will not rotate in the presence of the signal field, but will be "self-pinned". A hard-bias or exchange bias layer in not needed, also eliminating the need for Ni-Mn and its associated high-temperature process.
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公开(公告)号：SG30327A1
公开(公告)日：1996-06-01
申请号：SG1995000170
申请日：1995-03-27
Applicant: IBM
Inventor： GURNEY BRUCE ALVIN , MAURI DANIEL , HEIM DAVID EUGENE , WILHOIT DENNIS RICHARD , LEFAKIS HARALAMBOS , COFFEY KEVIN ROBERT , SPERIOSU VIRGIL SIMON
IPC: G11B5/39
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公开(公告)号：DE3672317D1
公开(公告)日：1990-08-02
申请号：DE3672317
申请日：1986-01-17
Applicant: IBM
Inventor： HEIM DAVID EUGENE
Abstract: A magnetic head has a pair of outer pole pieces (32, 34) spaced from a central pole piece (36) to define a pair of transducing gaps (28, 30). An individual coil (12, 14) is disposed between each of the outer pole pieces and the central pole piece. The coils (12, 14) are connected to control circuit means (Figure 8) which is operable to connect the coils in series for a write operation (so that the flux in the outer pole pieces is additive for writing), and to connect the coils in series opposition for a read operation (so that the flux produced in the central pole by a previously recorded magnetic transition in the magnetic recording medium adjacent to the transducing gaps is sensed additively in the coils).
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