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公开(公告)号：JP2001148110A
公开(公告)日：2001-05-29
申请号：JP2000307398
申请日：2000-10-06
Applicant: IBM
Inventor： CAREY MATTHEW JOSEPH , FULLERTON ERIC EDWARD , GURNEY BRUCE ALVIN , ROSEN HAL JERVIS , SCHABES MANFRED ERNST
IPC: G11B5/708 , C23C28/00 , C23C28/02 , G11B5/64 , G11B5/65 , G11B5/66 , G11B5/673 , G11B5/738 , H01F10/26
Abstract: PROBLEM TO BE SOLVED: To provide a magnetic recording medium for keeping good thermal stability and SNR and supporting ultra high-density recording. SOLUTION: This magnetic recording medium for a data storage device is constituted of at least two magnetic recording layers of ferromagnetic films, which are adhered to each other in an antiferromagnetic manner, while interposing a nonferromagnetic spacer film. Magnetic moment of one ferromagnetic film works in the direction antiparallel to that of the magnetic moment of the other ferromagnetic film. The balanced magnetic moment is shown as the difference between Mrt values of two ferromagnetic films, when the magnetic moment is shown by net product (Mrt) of residual magnetism (Mr) and thickness (t) in the magnetic recording layer. The decrease in Mrt is achieved, while the thermal stability of the recording medium is not deteriorated, because the volume of particles in ferromagnetic films adhered to each other in an antiferromagnetic manner is increased constructively. Very sharp magnetic transitions can be achieved by the reduced antimagnetic field and higher density of the bit lines can be obtained in this medium as a result.
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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：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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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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Patent Agency Ranking
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：GB2355018B
公开(公告)日：2004-02-11
申请号：GB0015023
申请日：2000-06-21
Applicant: IBM
Inventor： CAREY MATTHEW JOSEPH , FULLERTON ERIC EDWARD , GURNEY BRUCE ALVIN , ROSEN HAL JERVIS , SCHABES MANFRED ERNST
IPC: G11B5/708 , C23C28/00 , C23C28/02 , G11B5/64 , G11B5/65 , G11B5/66 , G11B5/673 , G11B5/738 , H01F10/26 , C23C14/14 , C23C14/16 , G11B5/62 , G11B5/84
Abstract: A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films antiferromagnetically coupled together across a nonferromagnetic spacer film. The magnetic moments of the two antiferromagnetically-coupled films are oriented antiparallel, and thus the net remanent magnetization-thickness product (Mrt) of the recording layer is the difference in the Mrt values of the two ferromagnetic films. This reduction in Mrt is accomplished without a reduction in the thermal stability of the recording medium because the volumes of the grains in the antiferromagnetically-coupled films add constructively. In a magnetic recording rigid disk application, the magnetic layer comprises two ferromagnetic films, each a granular film of a sputter deposited CoPtCrB alloy, separated by a Ru spacer film having a thickness to maximize the antiferromagnetic exchange coupling between the two CoPtCrB films. One of the ferromagnetic films is made thicker than the other, but the thicknesses are chosen so that the net moment in zero applied magnetic field is low, but nonzero.
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公开(公告)号：GB2355018A
公开(公告)日：2001-04-11
申请号：GB0015023
申请日：2000-06-21
Applicant: IBM
Inventor： CAREY MATTHEW JOSEPH , FULLERTON ERIC EDWARD , GURNEY BRUCE ALVIN , ROSEN HAL JERVIS , SCHABES MANFRED ERNST
IPC: G11B5/708 , C23C28/00 , C23C28/02 , G11B5/64 , G11B5/65 , G11B5/66 , G11B5/673 , G11B5/738 , H01F10/26 , C23C14/14 , C23C14/16 , G11B5/62 , G11B5/84
Abstract: A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films antiferromagnetically coupled together across a nonferromagnetic spacer film. The magnetic moments of the two antiferromagnetically-coupled films are oriented antiparallel, and thus the net remanent magnetisation-thickness product (Mrt) of the recording layer is the difference in the Mrt values of the two ferromagnetic films. This reduction in Mrt is accomplished without a reduction in the thermal stability of the recording medium because the volumes of the grains in the antiferromagnetically-coupled films add constructively. In a magnetic recording rigid disk application, the magnetic layer comprises two ferromagnetic films, each a granular film of a sputter deposited coPtCrB alloy, separated by a Ru spacer film having a thickness to maximise the antiferromagnetic exchange coupling between the two CoPtCrB films. One of the ferromagnetic films is made thicker than the other, but the thicknesses are chosen so that the net moment in zero applied magnetic field is low, but nonzero. In general the first and second ferromagnetic films are made of a material selected from Co, Fe, Ni and their alloys. Apart from ruthenium the spacer film may be formed of Cr, Rh, Ir, Cu and their alloys. The medium may be in the form of a disk which has an underlayer on the substrate and a protective overcoat formed on the magnetic recording layer.
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公开(公告)号：DE69132027T2
公开(公告)日：2000-09-14
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：DE69316708D1
公开(公告)日：1998-03-05
申请号：DE69316708
申请日：1993-11-01
Applicant: IBM
Inventor： BAUMGART PETER MICHAEL , DIENY BERNARD , GURNEY BRUCE ALVIN , NOZIERES JEAN-PIERRE , SPERIOSU VIRGIL SIMON , WILHOIT DENNIS RICHARD
Abstract: A magnetoresistive read sensor 30 based on the spin valve effect incorporates a multilayered, dual spin valve structure. The sensor read element includes first 31, second 35 and third 39 layers of ferromagnetic material separated from each other by layers of non-magnetic metallic material. The first and third layers of ferromagnetic material, i.e., the outer layers of the structure, have their magnetization orientation fixed, while the second, intermediate ferromagnetic layer is magnetically soft and has its magnetization oriented perpendicular to that of both the outer ferromagnetic layers in the absence of an applied magnetic field. In one preferred embodiment, the two outer ferromagnetic layers have their magnetizations fixed parallel to each other by exchange coupling with adjacent antiferromagnetic layers. In a second preferred embodiment, the directions or magnetization in the first and third layers of ferromagnetic material are aligned in an antiparallel orientation.
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