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公开(公告)号：SG89322A1
公开(公告)日：2002-06-18
申请号：SG200001463
申请日：2000-03-14
Applicant: IBM
Inventor： HARDAYAL SINGH GILL
Abstract: A dual GMR sensor with a single antiferromagnetic (AFM) pinned layer is provided which has a thinner overall stack thickness and additive spin valve effects to increase the sensitivity of the dual sensor and counterbiasing of the free layers of the dual sensor so as to render the sensor insensitive to a magnitude and orientation of a sense current. The single pinning layer reduces the thickness of the dual sensor permitting the employment of an antiparallel (AP) pinned layer structure for each of the spin valve sensors of the dual sensor. Further, a preferred material for the pinning layer is iridium manganese (IrMn) which reduces the pinning layer to 50 Å-80 Å.
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公开(公告)号：SG82686A1
公开(公告)日：2001-08-21
申请号：SG200001384
申请日：2000-03-10
Applicant: IBM
Inventor： HARDAYAL SINGH GILL
IPC: G11B5/39
Abstract: A tunnel junction sensor with a track width area which balances a ferromagnetic coupling field with an opposed tunneling sense current field generated by a tunneling sense current to achieve biasing of the magnetic moment of the free layer in a tunnel junction head. The ferromagnetic coupling field is generated in the same direction as the magnetic moment of the pinned layer which is in close proximity to the free layer. Absent any external forces, the orientation of the magnetic moment of the free layer aligns with the orientation of the magnetic moment of the pinned layer. For the tunnel junction sensor to work efficiently, the orientation of the magnetic moment of the free layer should be perpendicular to the orientation of the magnetic moment of the pinned layer. To accomplish biasing the magnetic moment of the free layer in the desired direction, the tunneling sense current is directed in the plane of the conductive layer in such a direction parallel to the ABS so as to create a tunneling sense current field antiparallel to the ferromagnetic coupling field. By balancing these two opposed fields, the orientation of the magnetic moment of the free layer may be oriented perpendicular to the orientation of the magnetic moment of the pinned layer. To force the tunneling sense current to flow in the plane of the conducting layer parallel to the track width, a non-conducting layer located between the conductive layer and a lead wherein the lead is preferably a first shield layer of the sensor.
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公开(公告)号：SG118135A1
公开(公告)日：2006-01-27
申请号：SG200203008
申请日：2002-05-20
Applicant: IBM
Inventor： HARDAYAL SINGH GILL
Abstract: A tunnel valve sensor has a flux guide which has at least one iron nitride (FeN) layer and preferably a lamination of iron nitride (FeN) and nickel iron molybdenum (NiFeMo) layers wherein in the first instance the read gap is reduced and in the second instance the read gap is reduced and the sensitivity of the read head is increased.
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公开(公告)号：SG103347A1
公开(公告)日：2004-04-29
申请号：SG200203009
申请日：2002-05-20
Applicant: IBM
Inventor： HARDAYAL SINGH GILL
Abstract: A tunnel valve sensor and flux guide has improved flux transfer therebetween by providing a magnetic oxide insulation layer which is located between and interfaces a back surface of the flux guide and a front surface of the tunnel valve sensor. Since this insulation layer has magnetic properties an increased amount of flux is transferred between the flux guide to the tunnel valve sensor for rotating a magnetic moment of a free layer in the tunnel valve sensor.
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公开(公告)号：SG100637A1
公开(公告)日：2003-12-26
申请号：SG200101492
申请日：2001-03-12
Applicant: IBM
Inventor： HARDAYAL SINGH GILL , CHRISTOPHER DANA KEENER , GAUTAM RATILAL PATEL
Abstract: The present invention provides a method and apparatus for performing automated spin valve combined pinned layer reset and hard bias initialization at the head gimbal assembly level. The reset combines a current pulse with an assisting magnetic field. The pinned layer reset and hard bias initialization is automated and performed by a single tool at the head gimbal assembly level to increase manufacturing throughput.
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Patent Agency Ranking
公开(公告)号：SG99922A1
公开(公告)日：2003-11-27
申请号：SG200104474
申请日：2001-07-23
Applicant: IBM
Inventor： HARDAYAL SINGH GILL
Abstract: A spin valve (SV) magnetoresistive sensor is provided having an AP-pinned layer, an AP-coupled free layer and a non-magnetic electrically conductive spacer layer sandwiched between the AP-pinned layer and the free layer. The AP-pinned layer comprises first and second ferromagnetic layers separated by an antiparallel coupling (APC) layer. The AP-coupled free layer comprises a third ferromagnetic layer of Co-Fe adjacent to the spacer layer, a fourth ferromagnetic layer of Co-Fe-Hf-O and an APC layer sandwiched between the third and fourth ferromagnetic layers. The easy axis of the Co-Fe third ferromagnetic layer has a transverse orientation while the easy axis of the Co-Fe-Hf-O fourth ferromagnetic layer has a longitudinal orientation due to its higher thermal stability resulting in a low net intrinsic uniaxial anisotropy Hk for the AP-coupled free layer. The Co-Fe-Hf-O material of the fourth ferromagnetic layer has high resistivity resulting in reduced sense current shunting by the free layer. In addition, the metal oxide material of the fourth ferromagnetic layer is known to cause specular scattering of electrons. The reduced sense current shunting and the specular scattering of electrons both contribute to improving the GMR coefficient of the SV sensor.
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7.发明专利
公开(公告)号：SG97817A1
公开(公告)日：2003-08-20
申请号：SG1999005414
申请日：1999-11-01
Applicant: IBM
Inventor： HARDAYAL SINGH GILL
Abstract: A method of making a read head includes forming a spin valve sensor with an antiparallel pinned layer that has an AP coupling film located between and interfacing first and second ferromagnetic films wherein the first and second ferromagnetic films are composed of Co90Fe10. Another aspect forms the spin valve sensor with a free layer which has a nickel iron (NiFe) film located between and interfacing third and fourth ferromagnetic films composed of Co90Fe10. Still another aspect forms the spin valve sensor with a sense current field (SCF) pinned layer that is spaced from the free layer and is pinned by sense current fields from other conductive layers of the spin valve sensor.
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公开(公告)号：SG84539A1
公开(公告)日：2001-11-20
申请号：SG1999003649
申请日：1999-07-24
Applicant: IBM
Inventor： HARDAYAL SINGH GILL
Abstract: An improved spin valve sensor (300) having a diffusion barrier (348) interposed between a free layer (318) and a spacer (322) where the spacer (322) is interposed between the free layer (318) and a pinned layer (320) such that diffusion between said free layer (318) and the spacer (322) is effectively prevented during thermal treatment of the improved spin valve sensor (300) during manufacture. The diffusion barrier (348) is an amorphous material having a high GMR. In one embodiment, a high proportion of Cobalt is used to attain desired GMR.
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公开(公告)号：GB2389448B
公开(公告)日：2005-02-09
申请号：GB0318492
申请日：2002-07-17
Applicant: IBM , MARIANA HDD B V , HITACHI GLOBAL STORAGE TECH
Inventor： HARDAYAL SINGH GILL
Abstract: A magnetic transducer (head) according to the invention includes a free layer structure comprising two free layers exchange coupled across a thin spacer structure of comprising two spacer layers of nonmagnetic material separated by a ferromagnetic nano-oxide layer (NOL). The spacer layers prevent the NOL from unnecessarily hardening the free layer(s). The spacer layers are preferably copper or copper oxide. The spacer layers preserve the NOL's property of specular scattering of conduction electrons which tends to increase the magnetoresistive response. A free layer structure including the exchange coupling spacer structure of the invention can be used in a dual spin valve configuration, but is also useful in a single spin valve configuration. The free layer of the invention is useful in conduction in-plane (CIP), as well as, conduction perpendicular to the plane (CPP) devices.
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公开(公告)号：SG78387A1
公开(公告)日：2001-02-20
申请号：SG1999004216
申请日：1999-08-30
Applicant: IBM
Inventor： HARDAYAL SINGH GILL , DOUGLAS JOHNSON WERNER
Abstract: A magnetic tunnel junction (MTJ) device for use as a magnetic field sensor in a magnetic disk drive or as a memory cell in a magnetic random access (MRAM) array has an antiferromagnetic (AFM) layer formed of electrically insulating antiferromagnetic material. The magnetic tunnel junction in the sensor is formed on a first shield, which also serves as an electrical lead, and is made up of a stack of layers forming an MTJ sensor stripe. The layers in the stack are an AFM layer, a pinned ferromagnetic layer exchange biased with the AFM layer so that its magnetic moment cannot rotate in the presence of an applied magnetic field, a free ferromagnetic layer whose magnetic moment is free to rotate in the presence of an applied magnetic field, and an insulating tunnel barrier layer disposed between the pinned layer and the free layer. The MTJ sensor stripe is generally rectangularly shaped with parallel side edges and a back edge and a front edge at the air bearing surface (ABS). The pinned layer extends away from the ABS beyond the back edge of the AFM layer to contact the first shield providing a path for sensing current to bypass the electrically insulating AFM layer and flow to the tunnel junction layer. A layer of electrically insulating material isolates the pinned layer and the first shield from the second shield which also serves as an electrical lead for the MTJ sensor.
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