Having Flux Guide Detail Patents (Class 360/321)
  • Patent number: 6888705
    Abstract: Several embodiments of a sense current perpendicular to the planes of the sensor (CPP) and flux guide type of read head has a gap between first and second shield layers at an air bearing surface (ABS) where the flux guide is located which is less than a gap between the first and second shield layers at a recessed location where the sensor is located. This reduced gap increases the linear bit density capability of the read head. A longitudinal bias stack (LBS) is located in the sensor stack. Several unique methods of construction are described for forming the magnetic head assemblies.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: May 3, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Robert Edward Fontana, Jr., Kuok San Ho, Tao Pan, Ching Hwa Tsang
  • Patent number: 6873499
    Abstract: A read head has a flux guide layer that is immediately adjacent (abuts) the back edge of a read sensor. The flux guide layer is made of a high resistance soft magnetic material that conducts magnetic flux from the back edge of the read sensor so that the magnetic response at the back edge of the read sensor is significantly higher than zero. This increases the efficiency of the read sensor. The material for the flux guide layer is A-B-C where A is selected from the group Fe and Co, B is selected from the group Hf, Y, Ta and Zr and C is selected from the group O and N. In a preferred embodiment A-B-C is Fe—Hf—O and the Ms? of the flux guide layer is greater than 50 times the Ms? of the read sensor layer where the read sensor layer is NiFe, Ms is saturation magnetization and ? is resistivity. Because of the flux guides high resistance current shunting losses are nearly eliminated.
    Type: Grant
    Filed: January 24, 2001
    Date of Patent: March 29, 2005
    Assignee: International Business Machines Corporation
    Inventors: Wen Yaung Lee, Tsann Lin, Daniele Mauri, David John Seagle
  • Patent number: 6850393
    Abstract: In a yoke type reproducing magnetic head, a magnetoresistance effect film can be arranged in the vicinity of a medium facing surface, so that sensitivity is improved. The yoke type reproducing magnetic head comprises: a pair of magnetic yokes which face each other via a magnetic gap, at least one of the pair of magnetic yokes extending from a medium facing surface to a position retracted from the medium facing surface; a magnetoresistance effect film which has a curved portion protruding toward the medium facing surface in the magnetic gap and which is magnetically connected to the magnetic yokes; and an electrode which is electrically connected to the magnetoresistance effect film.
    Type: Grant
    Filed: September 20, 2001
    Date of Patent: February 1, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Michiko Hara, Tomomi Funayama, Masatoshi Yoshikawa, Kohichi Tateyama, Hiroaki Yoda
  • Publication number: 20040257712
    Abstract: The present invention provides a magnetic head having improved characteristics, using a magnetoresistive device in which current flows across the film plane such as a TMR device. In a first magnetic head of the present invention, when the area of a non-magnetic layer is defined as a device cross-section area, and the area of a yoke is defined as a yoke area, viewed along the direction perpendicular to the surface of the substrate over which the yoke and the magnetoresistive device are formed, then the device cross-section area is not less than 30% of the yoke area, so that a resistance increase of the device cross-section area is suppressed. In a second magnetic head of the present invention, a magnetoresistive device is formed on a substrate, and a yoke is provided above a non-magnetic layer constituting the device.
    Type: Application
    Filed: July 22, 2004
    Publication date: December 23, 2004
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
  • Patent number: 6829819
    Abstract: A magnetoresistive device having a first pole, a second pole, and a first tapered pole pedestal therebetween and magnetically connected to the second pole. The first tapered pole has a width that increases with increasing distance away from the air bearing surface, ABS. The magnetoresistive device can also include a second tapered pole pedestal magnetically connected to the first pole, and separated from the first tapered pole pedestal by a write gap. The second tapered pole pedestal has a width that increases with increasing distance away from the air bearing surface. A method of the present invention includes defining the trackwidth of a write element by lapping a tapered pole pedestal. More specifically, the trackwidth is given by a known taper angle, a zero throat width, and a throat height, wherein the throat height is controlled precisely by lapping.
    Type: Grant
    Filed: December 11, 2001
    Date of Patent: December 14, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Billy W. Crue, Jr., Mark David Thomas, Zhupei Shi, Renuka Apparao
  • Patent number: 6804089
    Abstract: The objective of this invention is to provide a yoke-type magnetic head and a magnetic recording device in which Barkhausen noise is low. It is possible to induce a magnetic flux efficiently within a magnetic head by using a granular magnetic film that exhibits both soft magnetic properties and a high resistance, which suppresses any shunt of the flow of the sense current into the magnetic yokes, thus preventing any deterioration insensitivity. Since this means that eddy currents can be suppressed, even during use in high-frequency regions, the frequency response characteristics are also improved. In addition, since the magnetic grains within the granular magnetic film are nano-sized, the dimensions of magnetic domains therein are also miniaturized to match that size, and thus there is also substantially no movement of the magnetic domain walls and this miniaturization also makes it possible to suppress the generation of Barkhausen noise.
    Type: Grant
    Filed: April 29, 2003
    Date of Patent: October 12, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Yuichi Osawa, Masatoshi Yoshikawa, Hiroaki Yoda
  • Patent number: 6801410
    Abstract: A transducing head according to the present invention includes a pair of electrodes, a pair of biasing elements and a magnetoresistive sensor. The magnetoresistive sensor is positioned between the pair of electrodes. The magnetoresistive sensor includes a pair of flux guides and a free layer positioned substantially co-planar with and between the pair of flux guides. The pair of electrodes are for providing a sense current to the free layer in a direction substantially perpendicular to a plane of the free layer. The pair of biasing elements are positioned on opposing sides of the magnetoresistive sensor for providing longitudinal bias to the free layer.
    Type: Grant
    Filed: September 19, 2002
    Date of Patent: October 5, 2004
    Assignee: Seagate Technology LLC
    Inventors: Song Sheng Xue, Paul E. Anderson, Patrick Joseph Ryan
  • Patent number: 6798620
    Abstract: A magnetic head including a magnetic substrate for operating as a first electrode, a multi-layer film formed on a portion of the surface of the magnetic substrate an inter-layer insulating layer provided to cover side surfaces of the multi-layer film, a flux guide formed on surfaces of the multi-layer film and inter-layer insulating layers, a non-magnetic conductive layer formed on a surface of the flux guide, and a second electrode formed on a surface of the non-magnetic conductive layer, in which the multi-layer film includes a first magnetic layer formed on a portion of the surface of the magnetic substrate and includes a fixed layer, and a second magnetic layer including a non-magnetic layer formed on a surface of the first magnetic layer and a free layer formed on a surface of the non-magnetic layer.
    Type: Grant
    Filed: May 20, 2003
    Date of Patent: September 28, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Hideaki Adachi, Kenji Iijima, Hiroshi Sakakima, Yasunari Sugita
  • Patent number: 6792670
    Abstract: A method is provided for manufacturing a magnetoresistive device substructure. The substructure includes: a TMR element; a bias field inducing layer that covers the TMR element; and a front flux probe layer formed on the bias field inducing layer and introducing a signal flux to the TMR element. In the manufacturing method, the TMR element and a dummy element are first formed. The dummy element has a shape similar to the TMR element and located in a specific position with respect to the TMR element. Next, the bias field inducing layer is formed on the TMR element in a specific position referring to the position of the dummy element. At the same time, a dummy bias field inducing layer is formed in a position located off the dummy element. Next, the front flux probe layer and a dummy front flux probe layer are formed at the same time on the bias field inducing layer and the dummy element, respectively.
    Type: Grant
    Filed: March 16, 2001
    Date of Patent: September 21, 2004
    Assignee: TDK Corporation
    Inventors: Kazuki Sato, Noriaki Kasahara, Koji Shimazawa
  • Patent number: 6785100
    Abstract: The present invention provides a magnetic head having improved characteristics, using a magnetoresistive device in which current flows across the film plane such as a TMR device. In a first magnetic head of the present invention, when the area of a non-magnetic layer is defined as a device cross-section area, and the area of a yoke is defined as a yoke area, viewed along the direction perpendicular to the surface of the substrate over which the yoke and the magnetoresistive device are formed, then the device cross-section area is not less than 30% of the yoke area, so that a resistance increase of the device cross-section area is suppressed. In a second magnetic head of the present invention, a magnetoresistive device is formed on a substrate, and a yoke is provided above a non-magnetic layer constituting the device.
    Type: Grant
    Filed: April 9, 2001
    Date of Patent: August 31, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
  • Publication number: 20040160705
    Abstract: In a yoke type reproducing magnetic head, a magnetoresistance effect film can be arranged in the vicinity of a medium facing surface, so that sensitivity is improved. The yoke type reproducing magnetic head comprises: a pair of magnetic yokes which face each other via a magnetic gap, at least one of the pair of magnetic yokes extending from a medium facing surface to a position retracted from the medium facing surface; a magnetoresistance effect film which has a curved portion protruding toward the medium facing surface in the magnetic gap and which is magnetically connected to the magnetic yokes; and an electrode which is electrically connected to the magnetoresistance effect film.
    Type: Application
    Filed: February 17, 2004
    Publication date: August 19, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Michiko Hara, Tomomi Funayama, Masatoshi Yoshikawa, Kohichi Tateyama, Hiroaki Yoda
  • Patent number: 6757144
    Abstract: Various embodiments of a read head employ a bias stack which is in a sensor stack of the read head. The bias stack includes a biasing layer and is separated from a free layer in the sensor by a spacer layer. A magnetic moment of the free layer is longitudinally biased antiparallel to a magnetic moment of the biasing layer because of the coupling therebetween. The free layer is therefore more uniformly longitudinally biased than when hard bias layers are employed at first and second side surfaces of the sensor. Various methods are described for making the various read heads of the present invention.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: June 29, 2004
    Assignee: International Business Machines Corporation
    Inventors: Kashmira J. Carey, Robert Edward Fontana, Jr., Kuok San Ho, Tao Pan
  • Patent number: 6741431
    Abstract: The objective of this invention is to provide a yoke-type magnetic head and a magnetic recording device in which Barkhausen noise is low. It is possible to induce a magnetic flux efficiently within a magnetic head by using a granular magnetic film that exhibits both soft magnetic properties and a high resistance, which suppresses any shunt of the flow of the sense current into the magnetic yokes, thus preventing any deterioration insensitivity. Since this means that eddy currents can be suppressed, even during use in high-frequency regions, the frequency response characteristics are also improved. In addition, since the magnetic grains within the granular magnetic film are nano-sized, the dimensions of magnetic domains therein are also miniaturized to match that size, and thus there is also substantially no movement of the magnetic domain walls and this miniaturization also makes it possible to suppress the generation of Barkhausen noise.
    Type: Grant
    Filed: April 29, 2003
    Date of Patent: May 25, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Yuichi Osawa, Masatoshi Yoshikawa, Hiroaki Yoda
  • Publication number: 20040090705
    Abstract: A magnetic recording/reproducing apparatus includes a servo head amplifier, including first and second signal processors, comparator circuit, and tape speed controller. The first signal processor processes a first signal read from first servo device into a third signal, and the second signal processor processes a second signal read from second servo device into a fourth signal. The comparator circuit compares the third and fourth signals. If a signal output difference exists, the tape speed controller changes the magnetic tape transport speed, so that a signal is recorded to form a signal track with constant width. Therefore, it is possible to provide a magnetic head capable of stably recording signals to form signal tracks with constant width using servo technology, a magnetic recording apparatus including the magnetic head, and a magnetic recording/reproducing apparatus which can stably record signals to form signal tracks with constant width and restrict variations in reproduction signals.
    Type: Application
    Filed: November 6, 2003
    Publication date: May 13, 2004
    Applicant: Alps Electric Co., Ltd.
    Inventor: Katsuya Kikuiri
  • Patent number: 6728081
    Abstract: The invention provides a magnetoresistive effect sensor that is a yoke type magnetoresistive effect sensor having a tunnel magnetoresistive effect film, which is operated stably with suppressed Barkhausen noise, and provides a reproducing head and a magnetic disk apparatus that use the magnetoresistive effect sensor. The magnetoresistive effect sensor is provided with a tunnel magnetoresistive effect film, a pair of electrodes for supplying a current in the film thickness direction of the magnetoresistive effect film, and a magnetic flux guide for guiding a magnetic flux from the recording medium: surface to the magnetoresistive effect film, wherein the magnetic domain of a free layer of the tunnel type magnetoresistive effect film and the magnetic domain of the magnetic flux guide are both controllable together.
    Type: Grant
    Filed: April 21, 2003
    Date of Patent: April 27, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Reiko Arai, Yoshiaki Kawato, Katsuro Watanabe
  • Patent number: 6728080
    Abstract: A magnetic reproducing head and a magnetic recording head. The magnetic reproducing head includes a GMR or TMR magnetic sensor, and a flux guide for introducing a magnetic flux into the magnetic sensor. At least a portion of the flux guide includes a material which is capable of permitting the magnetic flux to pass therethrough at a temperature not lower than a predetermined temperature Tp, but not permitting the magnetic flux to pass therethrough at a temperature lower than Tp. Light is irradiated to only a portion of the flux guide to cause the temperature of the irradiated portion to rise up to Tp or more, thereby permitting a magnetic flux to pass only through the irradiated portion, thus narrowing the track width of magnetic reproducing head when detecting recorded information from the magnetic recording medium.
    Type: Grant
    Filed: March 16, 2001
    Date of Patent: April 27, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Kenchi Ito, Susumu Soeya
  • Publication number: 20040070889
    Abstract: A magnetoresistive effect element is a compound lamination including a first anti-ferromagnetic layer, a first fixed magnetic layer, a tunnel insulation layer, a free magnetic layer, a non-magnetic metal layer, a second fixed magnetic layer, and a second anti-ferromagnetic layer such that a TMR element and a SVMR element are formed, sharing the free magnetic layer.
    Type: Application
    Filed: June 19, 2003
    Publication date: April 15, 2004
    Applicant: Fujitsu Limited
    Inventors: Yiqun Zhang, Hideyuki Kikuchi, Masashige Sato, Kazuo Kobayashi, Hitoshi Kanai
  • Patent number: 6721139
    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.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: April 13, 2004
    Assignee: International Business Machines Corporation
    Inventor: Hardayal Singh Gill
  • Publication number: 20040061979
    Abstract: A magnetoresistive sensor for use in a data storage device has a recessed sensing element (magnetic tunnel junction, CPP spin valve, etc.) with an exchange biased sensing ferromagnetic (free) layer, and a flux guide that magnetically connects the sensing element to a sensing surface of the sensor. The free layer is selectively exchange biased by a layer of exchange bias material placed under non-active regions of the free layer that lie outside the sensing element and flux guide track widths. The flux guide is provided by extending the free layer from a forward edge of the sensing element to the sensor surface. Advantageously, the sensing element and the flux guide have equal track width so that magnetic flux directed from the flux guide into the sensing element is not diluted with consequent loss of sensitivity.
    Type: Application
    Filed: September 30, 2003
    Publication date: April 1, 2004
    Inventors: Kuok San Ho, Tao Pan
  • Publication number: 20040034991
    Abstract: A spin valve sensor is provided with a negative ferromagnetic coupling field −HFC for properly biasing a free layer and a spin filter layer is employed between the free layer and a capping layer for increasing the magnetoresistive coefficient dr/R of the spin valve sensor. A top portion of the free layer is oxidized for improving the negative ferromagnetic coupling field −HFC when the spin filter layer is employed for increasing the magnetoresistive coefficient dr/R.
    Type: Application
    Filed: June 30, 2003
    Publication date: February 26, 2004
    Applicant: Hitachi Global Storage Technologies
    Inventor: Mustafa Pinarbasi
  • Patent number: 6690526
    Abstract: A magnetic recording and reproducing head which includes a magnetic sensor, and a flux guide for introducing a magnetic flux into the magnetic sensor. At least a portion of the flux guide is constituted by a material which permits the magnetic flux to pass therethrough at a temperature of not lower than a predetermined temperature Tp, but not permit the magnetic flux to pass therethrough at a temperature of lower than Tp. Light is irradiated to only a portion of the flux guide to cause the temperature of the irradiated portion to rise up to Tp or more, thereby permitting a magnetic flux to pass only through the irradiated portion.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: February 10, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Kenchi Ito, Susumu Soeya
  • Patent number: 6680830
    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.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: January 20, 2004
    Assignee: International Business Machines Corporation
    Inventor: Hardayal Singh Gill
  • Patent number: 6680827
    Abstract: A current perpendicular-to-the-plane magnetoresistance (CPP-MR) device includes a first magnetic shield, a second magnetic shield, and a spin valve structure. The first and second magnetic shields are formed of an electrically conductive and magnetically shielding material. A read gap is defined between the first and second magnetic shields, and the spin valve structure is disposed between the first and second magnetic shields. The spin valve structure is electrically connected and magnetically separated from the first and second magnetic shields such that the first and second magnetic shields act as electrical contact leads.
    Type: Grant
    Filed: December 6, 2000
    Date of Patent: January 20, 2004
    Assignee: TDK Corporation
    Inventors: Shuxiang Li, Satoru Araki
  • Patent number: 6678126
    Abstract: The part of an MR element 25 which lies close to a medium-facing surface 10a overlaps that part of a flux-guiding element 24 which lies remote from the medium-facing surface 10a, with a second gap film 23b interposed between the elements 24 and 25. Further, the MR element 25 overlaps the flux-guiding element 24 for a distance that falls within a range of 15 to 25% of the length of the MR height of the element 25 as measured in a direction perpendicular to the medium-facing surface 10a.
    Type: Grant
    Filed: October 19, 2001
    Date of Patent: January 13, 2004
    Assignee: Sony Corporation
    Inventors: Toru Katakura, Takuji Matsuo, Eiji Nakashio, Junichi Sugawara, Seiji Onoe
  • Patent number: 6671136
    Abstract: The invention provides a magnetoresistive effect sensor that is a yoke type magnetoresistive effect sensor having a tunnel magnetoresistive effect film, which is operated stably with suppressed Barkhausen noise, and provides a reproducing head and a magnetic disk apparatus that use the magnetoresistive effect sensor. The magnetoresistive effect sensor is provided with a tunnel magnetoresistive effect film, a pair of electrodes for supplying a current in the film thickness direction of the magnetoresistive effect film, and a magnetic flux guide for guiding a magnetic flux from the recording medium surface to the magnetoresistive effect film, wherein the magnetic domain of a free layer of the tunnel type magnetoresistive effect film and the magnetic domain of the magnetic flux guide are both controllable together.
    Type: Grant
    Filed: March 19, 2001
    Date of Patent: December 30, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Reiko Arai, Yoshiaki Kawato, Katsuro Watanabe
  • Publication number: 20030235015
    Abstract: A flux guide protected magnetoresistive sensor in a tape drive read/write head is presented. The magnetoresistive sensor has a tape bearing surface, and includes a magnetoresistive sensing element and a flux guide disposed on a surface of the magnetoresistive sensing element to form a portion of the tape bearing surface.
    Type: Application
    Filed: June 25, 2002
    Publication date: December 25, 2003
    Inventor: Andrew L. Wu
  • Patent number: 6665152
    Abstract: Magnetic heads capable of recording and reading with high sensitivity and resolution are provided by minimizing the outflow of magnetic fluxes from a flux guide to magnetic shields while using a flux guide structure for an MR element. In the magnetic head, magnetic shields exposed on a surface opposite a magnetic recording medium (air bearing surface) and a flux guide exposed between the magnetic heads via a non-magnetic layer are provided, and magnetic fluxes are guided by the flux guide to a magnetoresistive (MR) element formed in a position not exposed on the air bearing surface. The height of the magnetic shields in a direction perpendicular to the air bearing surface is less than the distance from the air bearing surface to the MR element, and the lengthwise direction of the magnetic shields is in parallel to the air bearing surface in the vicinity of the position in which the flux guide is formed.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: December 16, 2003
    Assignee: Hitachi, Ltd.
    Inventor: Hiroaki Nemoto
  • Publication number: 20030223157
    Abstract: A transducing head according to the present invention includes a pair of electrodes, a pair of biasing elements and a magnetoresistive sensor. The magnetoresistive sensor is positioned between the pair of electrodes. The magnetoresistive sensor includes a pair of flux guides and a free layer positioned substantially co-planar with and between the pair of flux guides. The pair of electrodes are for providing a sense current to the free layer in a direction substantially perpendicular to a plane of the free layer. The pair of biasing elements are positioned on opposing sides of the magnetoresistive sensor for providing longitudinal bias to the free layer.
    Type: Application
    Filed: September 19, 2002
    Publication date: December 4, 2003
    Applicant: Seagate Technology LLC
    Inventors: Song Sheng Xue, Paul E. Anderson, Patrick Joseph Ryan
  • Patent number: 6657825
    Abstract: A magnetoresistive sensor for use in a data storage device has a recessed sensing element (magnetic tunnel junction, CPP spin valve, etc.) with an exchange biased sensing ferromagnetic (free) layer, and a flux guide that magnetically connects the sensing element to a sensing surface of the sensor. The free layer is selectively exchange biased by a layer of exchange bias material placed under non-active regions of the free layer that lie outside the sensing element and flux guide track widths. The flux guide is provided by extending the free layer from a forward edge of the sensing element to the sensor surface. Advantageously, the sensing element and the flux guide have equal track width so that magnetic flux directed from the flux guide into the sensing element is not diluted with consequent loss of sensitivity.
    Type: Grant
    Filed: August 2, 2001
    Date of Patent: December 2, 2003
    Assignee: International Business Machines Corporation
    Inventors: Kuok San Ho, Tao Pan
  • Publication number: 20030197982
    Abstract: The objective of this invention is to provide a yoke-type magnetic head and a magnetic recording device in which Barkhausen noise is low. It is possible to induce a magnetic flux efficiently within a magnetic head by using a granular magnetic film that exhibits both soft magnetic properties and a high resistance, which suppresses any shunt of the flow of the sense current into the magnetic yokes, thus preventing any deterioration insensitivity. Since this means that eddy currents can be suppressed, even during use in high-frequency regions, the frequency response characteristics are also improved. In addition, since the magnetic grains within the granular magnetic film are nano-sized, the dimensions of magnetic domains therein are also miniaturized to match that size, and thus there is also substantially no movement of the magnetic domain walls and this miniaturization also makes it possible to suppress the generation of Barkhausen noise.
    Type: Application
    Filed: April 29, 2003
    Publication date: October 23, 2003
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Yuichi Osawa, Masatoshi Yoshikawa, Hiroaki Yoda
  • Patent number: 6636391
    Abstract: A magnetoresistive sensor employing a magnetoresistive sensor film of a GMR film or a TMR film and a magnetic flux guide to ensure high sensitivity and high stability. Magnetization of a magnetic flux guide and a first ferromagnetic layer, which is a free layer of a GMR sensor film or a TMR sensor film, are made to antiferromagnetically couple to each other via a nonmagnetic intermediate layer 21. Since net magnetic moment has become small in the area in which the magnetoresistive sensor film is arranged, and an angle of magnetization of the ferromagnetic layer rotated by magnetic field which has been guided by the magnetic flux guide enlarges, high sensitivity can be obtained. When a longitudinal biasing layer is provide for the magnetic flux guide, longitudinal biasing magnetic field is applied to the ferromagnetic layer as well which is antiferromagnetically coupled to the magnetic flux guide, thus being able to suppress Barkhausen noise of both the magnetic flux guide and the ferromagnetic layer.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: October 21, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Katsuro Watanabe, Yoshiaki Kawato, Reiko Arai
  • Publication number: 20030193758
    Abstract: A magneto-resistive element includes a magnetic substrate; a magnetic layer; and a non-magnetic layer provided between the magnetic substrate and the magnetic layer.
    Type: Application
    Filed: May 20, 2003
    Publication date: October 16, 2003
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Hideaki Adachi, Kenji Iijima, Hiroshi Sakakima, Yasunari Sugita
  • Publication number: 20030193757
    Abstract: The objective of this invention is to provide a yoke-type magnetic head and a magnetic recording device in which Barkhausen noise is low. It is possible to induce a magnetic flux efficiently within a magnetic head by using a granular magnetic film that exhibits both soft magnetic properties and a high resistance, which suppresses any shunt of the flow of the sense current into the magnetic yokes, thus preventing any deterioration insensitivity. Since this means that eddy currents can be suppressed, even during use in high-frequency regions, the frequency response characteristics are also improved. In addition, since the magnetic grains within the granular magnetic film are nano-sized, the dimensions of magnetic domains therein are also miniaturized to match that size, and thus there is also substantially no movement of the magnetic domain walls and this miniaturization also makes it possible to suppress the generation of Barkhausen noise.
    Type: Application
    Filed: April 29, 2003
    Publication date: October 16, 2003
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Yuichi Osawa, Masatoshi Yoshikawa, Hiroaki Yoda
  • Publication number: 20030189797
    Abstract: The invention provides a magnetoresistive effect sensor that is a yoke type magnetoresistive effect sensor having a tunnel magnetoresistive effect film, which is operated stably with suppressed Barkhausen noise, and provides a reproducing head and a magnetic disk apparatus that use the magnetoresistive effect sensor. The magnetoresistive effect sensor is provided with a tunnel magnetoresistive effect film, a pair of electrodes for supplying a current in the film thickness direction of the magnetoresistive effect film, and a magnetic flux guide for guiding a magnetic flux from the recording medium: surface to the magnetoresistive effect film, wherein the magnetic domain of a free layer of the tunnel type magnetoresistive effect film and the magnetic domain of the magnetic flux guide are both controllable together.
    Type: Application
    Filed: April 21, 2003
    Publication date: October 9, 2003
    Inventors: Reiko Arai, Yoshiaki Kawato, Katsuro Watanabe
  • Patent number: 6629357
    Abstract: A magnetic head manufacturing method. In one embodiment, a wafer including magnetic head devices formed on the surface thereof are cut out into individual sliders. Photoresist is applied on the air bearing surfaces of the sliders and is then baked. The surface tension causes the photoresist at the peripheral regions of the air bearing surface to taper and become rounded or thinned. The air bearing surface is then uniformly dry-etched such that the peripheral regions of the air bearing surface are rounded in a tapered shape.
    Type: Grant
    Filed: February 10, 1999
    Date of Patent: October 7, 2003
    Assignee: Read-Rite SMI Corp.
    Inventor: Shin-ichi Akoh
  • Patent number: 6631055
    Abstract: A flux guided magnetic tunnel junction head includes a ferromagnetic pinned layer having an active region with a front edge recessed from a sensing surface, and a non-active region located between the sensing surface and the active region. The non-active region of the ferromagnetic pinned layer is rendered substantially non-conducting by chemically processing the ferromagnetic material of the ferromagnetic pinned layer in this region. The flux guided MTJ head also includes a ferromagnetic free layer having a front edge substantially coplanar with a sensing surface. The ferromagnetic free layer can function as a flux guide to direct magnetic flux from a recording medium to the tunnel junction. The location of the front edge of the ferromagnetic pinned layer prevents any shorting of the flux guided MTJ head occurring when the head is lapped at the sensing surface.
    Type: Grant
    Filed: June 8, 2001
    Date of Patent: October 7, 2003
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey R. Childress, Robert E. Fontana, Kuok San Ho, Ching H. Tsang
  • Publication number: 20030184924
    Abstract: A TMR element includes: a free layer formed on a lower gap layer; a tunnel barrier layer formed on the free layer; and a pinned layer formed on the tunnel barrier layer. The pinned layer and the tunnel barrier layer have sidewalls formed through etching. The TMR element further comprises a deposition layer made of a material that is separated by etching and deposits on the sidewalls and undergoes oxidation.
    Type: Application
    Filed: April 30, 2003
    Publication date: October 2, 2003
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Satoru Araki
  • Patent number: 6624988
    Abstract: A read head, which can be submicron, has an antiparallel (AP) coupled flux guide which is located at an air bearing surface and guides field signals from a rotating magnetic disk to a tunnel junction sensor which is recessed in the head. Because of the highly stable characteristics of the AP flux guide, first and second hard bias layers at the side edges of the flux guide are not required in order to stabilize the magnetization of the flux guide. The AP flux guide has first and second AP layers with oppositely oriented magnetizations so that the flux guide has a net magnetization which is the difference between the magnetizations of the first and second AP layers. These thicknesses are designed to provide a desired uniaxial anisotropy HK and magnetic softness of the AP flux guide.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: September 23, 2003
    Assignee: International Business Machines Corporation
    Inventor: Hardayal Singh Gill
  • Publication number: 20030151857
    Abstract: A flux guide type includes a magnetoresistive device for reading a signal flux, and a flux guide for transmitting the signal flux to the magnetoresistive device, wherein the flux guide includes a laminated film that includes a ferromagnetic layer, a non-magnetic layer and a ferromagnetic layer in this order, and the two ferromagnetic layers in the flux guide have antiparallel directions of magnetization with respect to the non-magnetic layer.
    Type: Application
    Filed: October 30, 2002
    Publication date: August 14, 2003
    Applicant: FUJITSU LIMITED
    Inventor: Hitoshi Kishi
  • Patent number: 6606225
    Abstract: The objective of this invention is to provide a yoke-type magnetic head and a magnetic recording device in which Barkhausen noise is low. It is possible to induce a magnetic flux efficiently within a magnetic head by using a granular magnetic film that exhibits both soft magnetic properties and a high resistance, which suppresses any shunt of the flow of the sense current into the magnetic yokes, thus preventing any deterioration insensitivity. Since this means that eddy currents can be suppressed, even during use in high-frequency regions, the frequency response characteristics are also improved. In addition, since the magnetic grains within the granular magnetic film are nano-sized, the dimensions of magnetic domains therein are also miniaturized to match that size, and thus there is also substantially no movement of the magnetic domain walls and this miniaturization also makes it possible to suppress the generation of Barkhausen noise.
    Type: Grant
    Filed: May 31, 2000
    Date of Patent: August 12, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Yuichi Osawa, Masatoshi Yoshikawa, Hiroaki Yoda
  • Publication number: 20030137780
    Abstract: Several embodiments of a sense current perpendicular to the planes of the sensor (CPP) and flux guide type of read head has a gap between first and second shield layers at an air bearing surface (ABS) where the flux guide is located which is less than a gap between the first and second shield layers at a recessed location where the sensor is located. This reduced gap increases the linear bit density capability of the read head. A longitudinal bias stack (LBS) is located in the sensor stack. Several unique methods of construction are described for forming the magnetic head assemblies.
    Type: Application
    Filed: January 18, 2002
    Publication date: July 24, 2003
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Robert Edward Fontana, Kuok San Ho, Tao Pan, Ching Hwa Tsang
  • Publication number: 20030137781
    Abstract: Various embodiments of a read head employ a bias stack which is in a sensor stack of the read head. The bias stack includes a biasing layer and is separated from a free layer in the sensor by a spacer layer. A magnetic moment of the free layer is longitudinally biased antiparallel to a magnetic moment of the biasing layer because of the coupling therebetween. The free layer is therefore more uniformly longitudinally biased than when hard bias layers are employed at first and second side surfaces of the sensor. Various methods are described for making the various read heads of the present invention.
    Type: Application
    Filed: January 18, 2002
    Publication date: July 24, 2003
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kashmira J. Carey, Robert Edward Fontana, Kuok San Ho, Tao Pan
  • Patent number: 6597546
    Abstract: A magnetic read head includes a tunnel junction sensor that has front and back surfaces that are recessed from the ABS and a flux guide that includes a ferromagnetic flux guide body with front and back surfaces wherein the front surface forms a portion of the ABS and the back surface is magnetically coupled to the tunnel junction sensor. A flux guide body has a middle portion between first and second side portions and first and second antiferromagnetic layers wherein the first antiferromagnetic layer is magnetically coupled to the first side portion and the second antiferromagnetic layer is magnetically coupled to the second side portion for pinning magnetic moments of the first and second side portions so that only a magnetic moment of the middle portion defines a track width of the sensor and responds to field signals from a rotating magnetic disk. The first and second antiferromagnetic layers have side walls which are perpendicular to the ABS and spaced apart by the track width.
    Type: Grant
    Filed: April 19, 2001
    Date of Patent: July 22, 2003
    Assignee: International Business Machines Corporation
    Inventor: Hardayal Singh Gill
  • Patent number: 6583967
    Abstract: A thin-film magnetic head includes: a TMR element; a lower electrode layer and an upper electrode layer for feeding a current used for signal detection to the TMR element; and an insulating layer provided between the lower and upper electrode layers and located adjacent to a side of the TMR element. The thin-film magnetic head further includes: an FFG layer that introduces a signal flux to the TMR element, the FFG layer touching one of the top surfaces of the TMR element and extending from the region in which the TMR element is located to the region in which the insulating layer is located; and a base film located between the FFG layer and the insulating layer and used as a base when the FFG layer is formed.
    Type: Grant
    Filed: June 14, 2001
    Date of Patent: June 24, 2003
    Assignee: TDK Corporation
    Inventors: Noriaki Kasahara, Koji Shimazawa
  • Patent number: 6552882
    Abstract: The present invention provides a yoke-type information reproduction head apparatus 100 having a magnetic sensor block 3 provided on the substrate 1 via a non-magnetic insulation layer 2. The magnetic sensor 3 includes a ferromagnetic tunnel junction element 5 which is sandwiched between an upper electrode block 6 and a lower electrode block 7 and which is connected to a magnetic domain control bias layer 8. This enables to obtain preferable S/N and bit error rate with reduced waveform noise. This invention provides a yoke-type information reproduction head having both of the characteristics of the front yoke 4-1 as a magnetic path and a lower electrode 7 as an electric path.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: April 22, 2003
    Assignee: NEC Corporation
    Inventor: Kazuhiko Hayashi
  • Patent number: 6538855
    Abstract: A magneto-resistive thin film magnetic head is provided, which magnetic head includes: a base; a first yoke provided on the base and separated by a gap into first and second portions, the first portion including a side which opposes a magnetic recording medium; a magneto-resistive element which is magnetically coupled to the first and second portions of the first yoke and detects a magnetic recording signal; a second yoke formed on the first yoke so as to form a reproducing head gap between the first portion of the first yoke and the second yoke; and a third yoke provided between the first portion of the first yoke and the base so as to be magnetically coupled to the first portion of the first yoke. The reproducing head gap, the first portion of the first yoke, the magneto-resistive element, the second portion of the first yoke, ad the second yoke form a cut magnetic circuit.
    Type: Grant
    Filed: November 21, 2000
    Date of Patent: March 25, 2003
    Assignee: Mitsumi Electric Co., Ltd.
    Inventors: Akira Nakamura, Morio Kondo, Norio Hasegawa, Yasuhiko Shinjo, Kenji Machida, Naoto Hayashi, Kazutoshi Mutou, Toshihiro Uehara, Junji Numazawa
  • Publication number: 20030048584
    Abstract: A transducing head has an air bearing surface and includes a top shield, a bottom shield, a read sensor, and a first flux guide. The top shield has both a substantially rectangular non-recessed portion and a substantially rectangular recessed portion. The non-recessed portion of the top shield extends from the air bearing surface to the recessed portion of the top shield and has a thickness greater than a thickness of the recessed portion of the top shield. The bottom shield has both a substantially rectangular non-recessed portion and a substantially rectangular recessed portion. The non-recessed portion of the bottom shield extends from the air bearing surface to the recessed portion of the bottom shield and has a thickness greater than a thickness of the recessed portion of the bottom shield. A length of the non-recessed portion of the top shield is substantially equal to a length of the non-recessed portion of the bottom shield.
    Type: Application
    Filed: October 24, 2002
    Publication date: March 13, 2003
    Applicant: Seagate Technology, Inc.
    Inventors: Dian Song, Nurul Amin
  • Publication number: 20030035249
    Abstract: A magnetoresistive sensor for use in a data storage device has a recessed sensing element (magnetic tunnel junction, CPP spin valve, etc.) with an exchange biased sensing ferromagnetic (free) layer, and a flux guide that magnetically connects the sensing element to a sensing surface of the sensor. The free layer is selectively exchange biased by a layer of exchange bias material placed under non-active regions of the free layer that lie outside the sensing element and flux guide track widths. The flux guide is provided by extending the free layer from a forward edge of the sensing element to the sensor surface. Advantageously, the sensing element and the flux guide have equal track width so that magnetic flux directed from the flux guide into the sensing element is not diluted with consequent loss of sensitivity.
    Type: Application
    Filed: August 2, 2001
    Publication date: February 20, 2003
    Applicant: International Business Machines Corporation
    Inventors: Kuok San Ho, Tao Pan
  • Publication number: 20030035254
    Abstract: A magnetic head using magneto-resistive effect includes a spin-valve type giantmagneto-resistive effect element or tunnel-typemagneto-resistive effect element type lamination layer structure portion in which a free layer 4 made of a soft magnetic material of which the magnetization is rotated in response to an external magnetic field, a fixed layer 6 made of a ferromagnetic material, an antiferromagnetic layer 7 for fixing the magnetization of this fixed layer 6 and a spacer layer 5, i.e., nonmagnetic conductive layer or a tunnel barrier layer are laminated with each other.
    Type: Application
    Filed: August 14, 2002
    Publication date: February 20, 2003
    Inventors: Akio Furukawa, Yoshihiko Kakihara
  • Patent number: 6519124
    Abstract: The present invention relates to a magneto-resistive tunnel junction read head having a multi-layer tunnel junction composed of a tunnel barrier layer sandwiched between a ferromagnetic free layer and a ferromagnetic pinned layer. Contiguous with the free layer is a hybrid, low-magnetization, T-shaped flux guide having a rear flux guide portion and a more narrow front flux guide portion. The front flux guide portion constitutes a part of an ABS (Air Bearing Surface). The rear portion entirely covers and overlaps the tunnel junction. The hybrid flux guide has a lower magnetization -than the sensing layer due to the addition of magnetization reducing elements such as Ta or Nb. Using this design, a tunnel junction read head has improved read performance and achieves a high and stable head output for adaptation to ultrahigh density recording.
    Type: Grant
    Filed: July 20, 2000
    Date of Patent: February 11, 2003
    Assignee: TDK Corporation
    Inventors: Olivier Redon, Satoru Araki