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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：IE80878B1
公开(公告)日：1999-05-05
申请号：IE970560
申请日：1997-07-30
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
IPC: G11B5/39
Abstract: A spin valve sensor structure for a magnetic read head is provided which employs first and second spin valve sensors separated by an insulative gap layer. Each spin valve sensor has a spacer layer sandwiched between a pinned layer and a laminated free layer. The magnetic orientations of the pinned layers are pinned in the same direction by first and second antiferromagnetic layers. The first laminated free layer includes a very thin ruthenium (Ru) layer sandwiched between first and second ferromagnetic free layers and the second laminated free layer includes a second very thin ruthenium (Ru) layer sandwiched between third and fourth ferromagnetic free layers. The second ferromagnetic free layer is thicker than the first ferromagnetic free layer and the third ferromagnetic free layer is thicker than the fourth ferromagnetic free layer. Upon the application of a magnetic field, the magnetic moments of the second and third ferromagnetic free layers rotate and the magnetic moments of the first and fourth ferromagnetic free layers follow due to strong exchange coupling. A first spacer layer is sandwiched between the first pinned layer and the second ferromagnetic free layer so that these layers produce a spin valve effect, and the second spacer layer is sandwiched between the second pinned layer and the fourth ferromagnetic free layer so that these layers produce a spin valve effect. Since the magnetic moments of the second and fourth ferromagnetic free layers are antiparallel, their rotations, relative to the direction of the magnetic moments of the pinned layer, produce responses of opposite polarity when excited by a magnetic field of one polarity. The opposite polarity responses are fed to a differential amplifier where they are combined for enhanced signal output and common mode noise rejection.
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公开(公告)号：BR9501495A
公开(公告)日：1995-11-14
申请号：BR9501495
申请日：1995-04-07
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
Abstract: A dual element magnetoresistive (MR) sensor is disclosed comprising two MR elements separated by a high resistivity conductive spacer material. A layer of hard bias material, which abuts one of the MR elements at each of its track edges, has a magnetization times thickness value substantially matched to that of the one MR element to bias it in one longitudinal direction. An exchange bias layer biases the other MR element by exchange coupling in an opposite longitudinal direction to achieve magnetic stabilization between the MR elements. The exchange bias layer abuts the other MR element at each of its track edges and has a magnetization times thickness value substantially matched to that of the other MR element. Alternatively, the exchange bias layer extends from one track edge to an opposite track edge in continuous underlying or overlying contact with the other MR element.
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公开(公告)号：SG53047A1
公开(公告)日：1998-09-28
申请号：SG1997002981
申请日：1997-08-19
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
Abstract: A disk drive system having a magnetoresistive (MR) sensor having four leads, two leads for providing sense current to an MR layer and two leads for providing current to a soft adjacent layer (SAL). The MR layer as well as the hard bias layers are electrically insulated from the SAL by an insulator. The voltages developed across the MR layer (voltages due to the presence of thermal asperities and voltages due to the presence of data fields) and the SAL (voltages due to the presence of thermal asperities) are applied to the inputs of a differential amplifier for substantial elimination of the thermal asperity signal.
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公开(公告)号：SG50880A1
公开(公告)日：1998-07-20
申请号：SG1997002956
申请日：1997-08-15
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
Abstract: A spin valve magnetoresistive (MR) read sensor is provided wherein the free and pinned layer magnetization are perpendicular to each other under quiescent conditions and the current flowing in the free MR layer is oriented to flow at a substantially 45 degree angle with respect to the free layer magnetization. The flow of the current at the 45 degree angle with respect to the free layer magnetization causes the AMR effect which is present in the free MR layer to be added to the spin valve sensor GMR effect and increases the overall magnetoresistive effect by about 25% to 33%.
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Patent Agency Ranking
公开(公告)号：IE970560A1
公开(公告)日：1998-03-25
申请号：IE970560
申请日：1997-07-30
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
IPC: G11B5/39
Abstract: A spin valve sensor structure for a magnetic read head is provided which employs first and second spin valve sensors separated by an insulative gap layer. Each spin valve sensor has a spacer layer sandwiched between a pinned layer and a laminated free layer. The magnetic orientations of the pinned layers are pinned in the same direction by first and second antiferromagnatic layers. The first laminated free layer includes a very thin ruthenium (Ru) layer sandwiched between first and second ferromagnetic free layers and the second laminated free layer includes a second very thin ruthenium (Ru) layer sandwiched between third and fourth ferromagnetic free layers. The second ferromagnetic free layer is thicker than the first ferromagnetic free layer and the third ferromagnetic free layer is thicker than the fourth ferromagnetic free layer. Upon the application of a magnetic field, the magnetic moments of the second and third ferromagnetic free layers rotate and the magnetic moments of the first and fourth ferromagnetic free layers follow due to strong exchange coupling. A first spacer layer is sandwiched between the first pinned layer and the second ferromagnetic free layer so that these layers produce a spin valve effect, and the second spacer layer is sandwiched between the second pinned layer and the fourth ferromagnetic free layer so that these layers produce a spin valve effect. Since the magnetic moments of the second and fourth ferromagnetic free layers are antiparallel, their rotations, relative to the direction of the magnetic moments of the pinned layer, produce responses of opposite polarity when excited by a magnetic field of one polarity. The opposite polarity responses are fed to a differtial amplifier where they are combined for enhanced signal output and common mode noise rejection.
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公开(公告)号：MY117184A
公开(公告)日：2004-05-31
申请号：MYPI9903032
申请日：1999-07-19
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
Abstract: A MAGNETIC TUNNEL JUNCTION (MTJ) DEVICE IS USABLE AS A MAGNETIC FIELD SENSOR IN MAGNETIC DISK DRIVES OR AS A MEMORY CELL IN A MAGNETIC RANDOM ACCESS (MRAM) ARRAY. THE MTJ DEVICE HAS A FERROMAGNETIC ANTIPARALLEL (AP)-PINNED LAYER COMPRISING A FIRST FERROMAGNETIC LAYER, A SECOND FERROMAGNETIC LAYER AND AN ANTIPARALLEL COUPLING (APC) LAYER DISPOSED BETWEEN THE FIRST AND SECOND FERROMAGNETIC LAYERS, A FREE FERROMAGNETIC LAYER AND AN INSULATING TUNNEL BARRIER LAYER DISPOSED BETWEEN THE FIRST FERROMAGNETIC LAYER OF THE AP-PINNED LAYER AND THE FREE FERROMAGNETIC LAYER. THE MAGNETIZATION OF THE AP-PINNED LAYER IS ORIENTED IN THE PLANE OF THE LAYER BUT IS FIXED SO AS NOT TO BE ABLE TO ROTATE IN THE PRESENCE OF AN APPLIED MAGNETIC FIELD IN THE RANGE OF INTEREST. THE MAGNETIZATION OF THE FREE FERROMAGNETIC LAYER IS ABLE TO BE ROTATED .IN THE PLANE OF THE LAYER RELATIVE TO THE FIXED MAGNETIZATION OF THE FERROMAGNETIC AP-PINNED LAYER. THE SECOND FERROMAGNETIC LAYER OF THE AP-PINNED LAYER IS FORMED OF A HIGH COERCIVITY MAGNETIC MATERIAL WHICH FIXES THE MAGNETIZATION DIRECTION OF THE AP-PINNED LAYER IN A DIRECTION PERPENDICULAR TO THE AIR BEARING SURFACE. THE NET MAGNETIC MOMENT OF THE AP-PINNED LAYER IS MADE TO BE NEAR ZERO TO MINIMIZE MAGNETOSTATIC INTERACTION OF THE AP-PINNED LAYER WITH THE FREE LAYER. (FIGURE 3)
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公开(公告)号：SG77708A1
公开(公告)日：2001-01-16
申请号：SG1999003850
申请日：1999-08-07
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
IPC: G01R33/09 , C22C19/07 , G01R33/06 , G11B5/39 , H01F10/16 , H01F10/32 , H01L43/08 , G11B5/187 , G06F3/033 , G09F9/35 , G11C29/00 , G06F13/00 , G06F12/14
Abstract: A magnetic tunnel junction (MTJ) device is usable as a magnetic field sensor in magnetic disk drives or as a memory cell in a magnetic random access (MRAM) array. The MTJ device has a ferromagnetic antiparallel (AP)-pinned layer comprising a first ferromagnetic layer, a second ferromagnetic layer and an antiparallel coupling (APC) layer disposed between the first and second ferromagnetic layers, a free ferromagnetic layer and an insulating tunnel barrier layer disposed between the first ferromagnetic layer of the AP-pinned layer and the free ferromagnetic layer. The magnetization of the AP-pinned layer is oriented in the plane of the layer but is fixed so as not to be able to rotate in the presence of an applied magnetic field in the range of interest. The magnetization of the free ferromagnetic layer is able to be rotated in the plane of the layer relative to the fixed magnetization of the ferromagnetic AP-pinned layer. The second ferromagnetic layer of the AP-pinned layer is formed of a high coercivity magnetic material which fixes the magnetization direction of the AP-pinned layer in a direction perpendicular to the air bearing surface. The net magnetic moment of the AP-pinned layer is made to be near zero to minimize magnetostatic interaction of the AP-pinned layer with the free layer.
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公开(公告)号：SG60098A1
公开(公告)日：1999-02-22
申请号：SG1997002863
申请日：1997-08-08
Applicant: IBM
Inventor： GILL HARDAYAL SINGH
IPC: G11B5/39
Abstract: A spin valve sensor structure for a magnetic read head is provided which employs first and second spin valve sensors separated by an insulative gap layer. Each spin valve sensor has a spacer layer sandwiched between a pinned layer and a laminated free layer. The magnetic orientations of the pinned layers are pinned in the same direction by first and second antiferromagnetic layers. The first laminated free layer includes a very thin ruthenium (Ru) layer sandwiched between first and second ferromagnetic free layers and the second laminated free layer includes a second very thin ruthenium (Ru) layer sandwiched between third and fourth ferromagnetic free layers. The second ferromagnetic free layer is thicker than the first ferromagnetic free layer and the third ferromagnetic free layer is thicker than the fourth ferromagnetic free layer. Upon the application of a magnetic field, the magnetic moments of the second and third ferromagnetic free layers rotate and the magnetic moments of the first and fourth ferromagnetic free layers follow due to strong exchange coupling. A first spacer layer is sandwiched between the first pinned layer and the second ferromagnetic free layer so that these layers produce a spin valve effect, and the second spacer layer is sandwiched between the second pinned layer and the fourth ferromagnetic free layer so that these layers produce a spin valve effect. Since the magnetic moments of the second and fourth ferromagnetic free layers are antiparallel, their rotations, relative to the direction of the magnetic moments of the pinned layer, produce responses of opposite polarity when excited by a magnetic field of one polarity. The opposite polarity responses are fed to a differential amplifier where they are combined for enhanced signal output and common mode noise rejection.
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公开(公告)号：SG54542A1
公开(公告)日：1998-11-16
申请号：SG1997002861
申请日：1997-08-08
Applicant: IBM
Inventor： GILL HARDAYAL SINGH , PINARBASI MUSTAFA
Abstract: A high magnetization, high resistivity, low corrosion and near zero magnetostriction soft adjacent layer (SAL) is provided for a magnetoresistive (MR) sensor of a read head. The MR sensor may either be an anisotropic MR (AMR) sensor or a spin valve sensor. In both sensors the SAL is CoHfNb or CoHfNbFe. The Hf is added to reduce corrosion and the Hf and Nb are balanced to provide near zero magnetostriction. The addition of Fe is an enhancer for reducing negative magnetostriction without diluting the magnetism of the alloy. Since CoHfNb has significantly higher magnetization than NiFeCr the SAL layer of CoHfNb can be thinner than the SAL of NiFeCr which results in a significantly higher resistance SAL. The higher resistance SAL equates to less shunting of the sense current through the SAL and better signal performance of the MR read head.
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