公开(公告)号：SG53048A1

公开(公告)日：1998-09-28

申请号：SG1997002983

申请日：1997-08-19

Applicant: IBM

Inventor： GILL HARDAYAL SINGH

IPC: G11B5/39

Abstract: A magnetoresistive (MR) sensor having end regions separated from each other by a central region. Hard bias layers disposed in the end regions longitudinally bias an MR layer which is formed in the central region. A soft adjacent layer (SAL) is utilized to transversely bias the MR layer. The MR layer and the hard bias layers are electrically insulated from the SAL by an insulator. The SAL magnetization is fixed through exchange coupling with an antiferromagnetic layer. Separating the MR layer and the hard bias layers from the SAL by an insulator prevents the sense current from flowing in the SAL thus improving the MR effect.

公开(公告)号：SG53041A1

公开(公告)日：1998-09-28

申请号：SG1997002927

申请日：1997-08-13

Applicant: IBM

Inventor： GILL HARDAYAL SINGH

IPC: G01R33/09 ,  G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/39 ,  G11B5/48 ,  G11B19/04 ,  H01F10/00 ,  H01F10/08 ,  H01F10/32 ,  H01L43/08

Abstract: A disk drive system having a spin valve (SV) magnetoresistive (MR) sensor having four leads, two leads for providing sense current to an SV element and two leads for providing current to an asperity compensation layer (ACL). The SV element as well as the hard bias layers are electrically insulated from the ACL by an antiferromagnetic layer made of an insulating material. The voltages developed across the SV element (voltages due to the presence of thermal asperities and voltages due to the presence of data fields) and the ACL (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.

公开(公告)号：SG53025A1

公开(公告)日：1998-09-28

申请号：SG1997002760

申请日：1997-08-01

Applicant: IBM

Inventor： GILL HARDAYAL SINGH

IPC: G11B5/00 ,  G11B5/39

Abstract: A self-biasing magnetoresistive (MR) spin valve sensor is provided which does not require an antiferromagnetic layer for orienting magnetizations. A non-magnetic electrically-conducting spacer layer is sandwiched between ferromagnetic free and pinned layers. First and second leads are connected to the spin valve sensor for conducting a sense current therethrough. Because of a magnetic coupling between the free and pinned layers, there are ferromagnetic coupling fields HFC in the free and pinned layers which are parallel with respect to one another and are directed in a first direction when the sense current is conducted. When the sense current is conducted there is also a stray demagnetization field HDEMAG which is induced into the free layer from the pinned layer. A first flux guide is magnetically coupled to first edges of the layers at the ABS and a second flux guide is magnetically coupled to second edges of the free layer recessed from the ABS so that the effect of the demagnetization field HDEMAG on the free layer is at least minimized and preferably zero. The sense current is directed through the spin valve sensor so that the sense current field from the pinned layer balances the ferromagnetic coupling on the free layer and the sense current field from the free layer adds to the ferromagnetic coupling on the pinned layer. Accordingly, the magnetic moment of the free layer is free to rotate as influenced by field signals from the rotating magnetic disk and the magnetic moment of the pinned layer is pinned in a pre-selected direction perpendicular to the ABS.

公开(公告)号：MY122384A

公开(公告)日：2006-04-29

申请号：MYPI9904722

申请日：1999-11-01

Applicant: IBM

Inventor： GILL HARDAYAL SINGH

IPC: G11B5/62 ,  G11B5/012 ,  G11B5/39

Abstract: THE PRESENT INVENTION IS AN EXTERNAL FIELD STABILIZED AND NEAR ZERO MAGNETOSTRICTIVE DOUBLE SPIN VALVE SENSOR WITH GIANT MAGNETORESISTIVE (GMR) ENHANCING, ANTIPARALLEL PINNED AND SENSE CURRENT FIELD PINNED LAYERS. IN A PREFERRED EMBODIMENT OF THE INVENTION THE AP PINNED LAYER HAS FIRST AND SECOND FILMS THAT ARE MADE OF COBALT IRON (CO90FEL0). IN ORDER TO ENHANCE THE SPIN DEPENDENT SCATTERING FIRST AND SECOND GMR ENHANCING LAYERS ARE EMPLOYED WHICH ARE ALSO CONSTRUCTED OF COBALT IRON (CO90FE10). FURTHER, IN ORDER TO DOUBLE THE SPIN VALVE EFFECT A SENSE CURRENT FIELD (SCF) PINNED LAYER IS EMPLOYED WHICH IS PINNED IN THE SAME DIRECTION AS THE SECOND FILM OF THE AP PINNED LAYER. THE SCF PINNED LAYER IS ALSO CONSTRUCTED OF COBALT IRON (CO90FELO). IN THE PREFERRED EMBODIMENT ALL OF THE MAGNETIC LAYERS ARE CONSTRUCTED OF COBALT IRON (CO90FEL0) SO THAT THEIR MAGNETIC MOMENTS ARE RETURNED TO THEIR ORIGINAL POSITIONS AFTER THE OCCURRENCE OF AN EXTERNAL FIELD. FURTHER, THE COBALT IRON (CO90FE10) HAS NEAR ZERO MAGNETOSTRICTION SO THAT STRESS INDUCED ANISOTROPY DOES NOT ALTER THE MAGNETIC PROPERTIES OF THESE LAYERS. THE HIGH RESISTANCE OF COBALT IRON (CO90FEL0) IN THE AP PINNED LAYER AND THE SCF PINNED LAYER ENSURES THAT A MINIMUM AMOUNT OF SENSE CURRENT FIELD IS SHUNTED. FIG 11

公开(公告)号：AT282884T

公开(公告)日：2004-12-15

申请号：AT02732932

申请日：2002-05-30

Applicant: IBM

Inventor： GILL HARDAYAL SINGH

IPC: G11B5/31 ,  G11B5/39 ,  G11B5/40 ,  G11B5/012

Abstract: A read head includes electrically conductive ferromagnetic first and second yoke layers and a tunnel valve sensor which is recessed from the ABS and is located between the first and second yoke layers. The first and second yoke layers extend to an air bearing surface (ABS) for conducting flux to the sensor and extend into the head beyond the sensor. A bottom copper structure interfaces a bottom surface of the tunnel valve sensor and a top copper structure interfaces a top surface of the tunnel valve sensor. In a first embodiment of the invention, the first and second copper structures conduct heat from the sensor to the first and second yoke layers respectively, and in a second embodiment of the invention the bottom copper structure conducts heat to a substrate while the top copper structure conducts from the sensor to the second yoke layer. Further, in the first embodiment the first and second yoke layers serve as leads for a tunneling current while in the second embodiment the bottom copper structure and the second yoke layer serve as leads for the tunneling current.

公开(公告)号：SG63839A1

公开(公告)日：1999-03-30

申请号：SG1998000791

申请日：1998-04-27

Applicant: IBM

Inventor： GILL HARDAYAL SINGH

IPC: G11B5/00 ,  G11B5/012 ,  G11B5/39 ,  G11B5/30

Abstract: A thin film magnetoresistive (MR) spin valve read sensor is provided which has positive and negative read signal symmetry about a zero bias point of a transfer curve upon sensing positive and negative magnetic incursions of equal magnitude from a moving magnetic medium, the sensor including a ferromagnetic free layer which has a magnetic moment which is free to rotate in first and second directions from a position which corresponds to the zero bias point upon sensing the positive and negative magnetic incursions respectively, an antiparallel pinned layer, an antiferromagnetic layer immediately adjacent the antiparallel pinned layer which pins the magnetic moment of the antiparallel pinned layer along a pinned direction, an electrically conductive nonmagnetic spacer layer sandwiched between the free layer and the antiparallel pinned layer so that, upon sensing the positive and negative magnetic incursions, the magnetic moment of the free layer rotates in the first and second directions relative to the pinned direction of the magnetic moment of the pinned layer, thus causing an increase or decrease in magnetoresistance respectively, and a sense current source for applying a sense current through the sensor in a predetermined direction and of a predetermined magnitude so that, in response to the increase and decrease in magnetoresistance, the sensor produces positive and negative read signal symmetry about the zero bias point.

公开(公告)号：SG43377A1

公开(公告)日：1997-10-17

申请号：SG1996010141

申请日：1996-06-24

Applicant: IBM

Inventor： GILL HARDAYAL SINGH ,  GURNEY BRUCE A

IPC: G01R33/09 ,  G11B5/012 ,  G11B5/02 ,  G11B5/39 ,  H01L41/00

Abstract: A magnetoresistive (MR) sensor comprises a dual differential spin valve structure. Each of the spin valves comprise first (free) and second (pinned) layers of ferromagnetic material separated by a thin film layer of nonmagnetic material. The magnetization direction of the pinned layers of ferromagnetic material in each spin valve is fixed, and their magnetization is set antiparallel to each other. 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 free layers of ferromagnetic material as a function of the magnetic field being sensed.

公开(公告)号：SG32325A1

公开(公告)日：1996-08-13

申请号：SG1995000112

申请日：1995-03-16

Applicant: IBM

Inventor： GILL HARDAYAL SINGH ,  PINARBASI MUSTAFA

IPC: G01R33/09