Patents by Inventor Takeo Kagami

Takeo Kagami has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8867168
    Abstract: A magnetic head includes a main pole, a write shield, and a return path section. The write shield includes first and second shield portions located on opposite sides of the main pole in the track width direction. The return path section includes first and second yoke portions located on opposite sides of the main pole in the track width direction. The first yoke portion is connected to the first shield portion. The second yoke portion is connected to the second shield portion. A coil surrounds at least part of the entire outer periphery of the main pole when viewed from a medium facing surface.
    Type: Grant
    Filed: December 7, 2012
    Date of Patent: October 21, 2014
    Assignee: TDK Corporation
    Inventors: Norikazu Ota, Masahiro Saito, Taro Oike, Takeo Kagami, Yosuke Antoku, Kenkichi Anagawa, Kenta Hara, Tetsuro Sasaki, Shingo Miyata, Katsuki Kurihara
  • Publication number: 20140160597
    Abstract: A magnetic head includes a main pole, a write shield, and a return path section. The write shield includes first and second shield portions located on opposite sides of the main pole in the track width direction. The return path section includes first and second yoke portions located on opposite sides of the main pole in the track width direction. The first yoke portion is connected to the first shield portion. The second yoke portion is connected to the second shield portion. A coil surrounds at least part of the entire outer periphery of the main pole when viewed from a medium facing surface.
    Type: Application
    Filed: December 7, 2012
    Publication date: June 12, 2014
    Applicant: TDK CORPORATION
    Inventors: Norikazu OTA, Masahiro SAITO, Taro OIKE, Takeo KAGAMI, Yosuke ANTOKU, Kenkichi ANAGAWA, Kenta HARA, Tetsuro SASAKI, Shingo MIYATA, Katsuki KURIHARA
  • Patent number: 8559133
    Abstract: A perpendicular magnetic write head includes: a magnetic pole having an end face on an air bearing surface; and side shield layers each having an end face on the air bearing surface, and arranged on both sides, in a write track width direction, of the magnetic pole with a side gap in between. The end face of the magnetic pole has a geometry in which a width at a trailing edge is larger than a width at a leading edge. Relationship D1<D2, D1<D3, and D3?D2 are satisfied in the air bearing surface, where D1 is a gap length of the side gap at the trailing edge, D2 is a gap length of the side gap at the leading edge, and D3 is a gap length of the side gap at any position between the trailing edge and the leading edge.
    Type: Grant
    Filed: June 1, 2009
    Date of Patent: October 15, 2013
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Takeo Kagami, Tatsuhiro Nojima, Hisayoshi Watanabe, Michitaka Nishiyama
  • Patent number: 8427790
    Abstract: A thin film magnetic head includes a magnetoresistive element having a recording-medium-facing-surface which is to be faced with a magnetic recording medium; a magnetic bias layer located on a side opposite to the recording-medium-facing-surface of the magnetoresistive element, and applying a bias magnetic field to the magnetoresistive element in a direction orthogonal to the recording-medium-facing-surface; and a resistive film pattern having the recording-medium-facing-surface, the resistive film pattern being located side by side with the magnetoresistive element in a track-width direction.
    Type: Grant
    Filed: June 30, 2008
    Date of Patent: April 23, 2013
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Kazuki Sato, Yohei Koyanagi, Takayasu Kanaya, Takeo Kagami
  • Patent number: 8300359
    Abstract: A perpendicular magnetic write head includes: a magnetic pole; a pair of side shields on both sides, in a write-track width direction, of the magnetic pole with respective side gaps in between; a trailing shield on a trailing side of the magnetic pole and the pair of side shields with a trailing gap in between. Each of the magnetic pole, the side shield, the trailing shield, the side gap, and the trailing gap has an end face exposed on an air bearing surface. The trailing gap has a first regional part and a second regional part. The first regional part separates a trailing edge of the magnetic pole from the trailing shield, and the second regional part separates the pair of side shields from the trailing shield. All or a part of the second regional part has a thickness larger than a thickness of the first regional part.
    Type: Grant
    Filed: December 30, 2009
    Date of Patent: October 30, 2012
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Katsuki Kurihara, Kenkichi Anagawa, Takeo Kagami
  • Patent number: 8240026
    Abstract: A method for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.
    Type: Grant
    Filed: September 24, 2008
    Date of Patent: August 14, 2012
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
  • Patent number: 8233237
    Abstract: A main magnetic-pole layer is provided with, at the tip end portion thereof, a trailing shied on the trailing side via a non-magnetic gap layer, and the non-magnetic gap layer includes therein one or more magnetic layers. This magnetic layer appropriately controls the amount of magnetic fluxes coming from the tip end portion of the main magnetic-pole layer for capturing into the trailing shield because the magnetic fluxes coming from the tip end portion of the main magnetic-pole layer go through the magnetic layer before being captured into the trailing shield.
    Type: Grant
    Filed: June 21, 2010
    Date of Patent: July 31, 2012
    Assignee: TDK Corporation
    Inventors: Kenkichi Anagawa, Katsuki Kurihara, Takeo Kagami, Kei Hirata, Minoru Ota
  • Patent number: 8144427
    Abstract: The present invention relates to a magnetic head, a head assembly, and a magnetic recording/reproducing apparatus which are capable of effectively detecting thermal asperity. The magnetic head according to the present invention includes a heat-generating resistor, a recording coil, and a resistive element. The heat-generating resistor is adapted to generate heat when power is fed thereto so that the heat generation causes at least a part of the air bearing surface to thermally expand and protrude. The recording coil is adapted to generate a recording magnetic field, and the resistive element is disposed closer to the air bearing surface than the recording coil and connected in series or in parallel with the heater. Thus, the resistive element can share a common wiring with the heater for power feeding, which eliminates the waste of wiring and achieves miniaturization.
    Type: Grant
    Filed: November 20, 2008
    Date of Patent: March 27, 2012
    Assignee: TDK Corporation
    Inventors: Yosuke Antoku, Takeo Kagami, Katsuki Kurihara, Taro Oike, Masashi Sano
  • Patent number: 8117736
    Abstract: A method of lapping a magnetic head slider includes a step of lapping a lapping surface of a row bar provided with a plurality of MR read head elements arranged along at least one line, a step of obtaining at least one output signal from at least one of the plurality of MR read head elements of the row bar during lapping, the at least one output signal corresponding to element resistance, a step of detecting at least one peak value of the obtained at least one output signal, and a step of controlling an amount of lapping of the row bar depending upon the detected at least one peak value.
    Type: Grant
    Filed: December 11, 2008
    Date of Patent: February 21, 2012
    Assignee: TDK Corporation
    Inventors: Naoki Ohta, Takeo Kagami
  • Patent number: 8085038
    Abstract: A noise-testing method for a thin-film magnetic head with an MR read head element and a heating unit capable of applying a heat and a stress to the MR read head element, includes a step of applying alternately and discontinuously with each other an electrical power having a first level and an electrical power having a second level higher than the first level to the heating unit, and a step of evaluating the thin-film magnetic head by measuring a noise output or noise outputs obtained from the MR read head element when the electrical power or the electrical powers are applied to the heating unit.
    Type: Grant
    Filed: May 25, 2007
    Date of Patent: December 27, 2011
    Assignees: TDK Corporation, SAE Magnectics (H.K.) Ltd.
    Inventors: Takumi Uesugi, Takeo Kagami, Tetsuro Sasaki, Kei Hirata, Masaru Hirose, Chi Man Lee, Kwok Piu Tso
  • Publication number: 20110310510
    Abstract: A main magnetic-pole layer is provided with, at the tip end portion thereof, a trailing shied on the trailing side via a non-magnetic gap layer, and the non-magnetic gap layer includes therein one or more magnetic layers. This magnetic layer appropriately controls the amount of magnetic fluxes coming from the tip end portion of the main magnetic-pole layer for capturing into the trailing shield because the magnetic fluxes coming from the tip end portion of the main magnetic-pole layer go through the magnetic layer before being captured into the trailing shield.
    Type: Application
    Filed: June 21, 2010
    Publication date: December 22, 2011
    Applicant: TDK CORPORATION
    Inventors: Kenkichi ANAGAWA, Katsuki Kurihara, Takeo Kagami, Kei Hirata, Minoru Ota
  • Patent number: 8077436
    Abstract: A magnetoresistance effect element comprises: a magnetoresistive stack including: first, second and third magnetic layers whose magnetization directions change in accordance with an external magnetic field, said second magnetic layer being located between said first magnetic layer and the third magnetic layer; a first non-magnetic intermediate layer sandwiched between said first and second magnetic layers; and a second non-magnetic intermediate layer sandwiched between said second and third magnetic layers; wherein sense current is adapted to flow in a direction perpendicular to a film plane; a bias magnetic layer provided on an opposite side of said magnetoresistive stack from an air bearing surface.
    Type: Grant
    Filed: March 20, 2008
    Date of Patent: December 13, 2011
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Satoshi Miura, Tomohito Mizuno, Takeo Kagami
  • Publication number: 20110262632
    Abstract: A magnetoresistive effect (MR) element, a thin-film magnetic head having the MR element, a method for manufacturing the MR element, and a method for manufacturing the thin-film magnetic head are disclosed. The MR element, which uses electric current in a direction perpendicular to layer planes, includes a lower electrode layer, a MR multilayered structure formed on the lower electrode layer, a magnetic domain controlling bias layer that is disposed on both sides of the MR multilayered structure along the track-width direction and is made of a material at least partially including an hcp structure, a metal layer made of a material having a bcc structure formed on the magnetic domain controlling bias layer and the MR multilayered structure to cover the magnetic domain controlling bias layer and the MR multilayered structure, and an upper electrode layer formed on the metal layer.
    Type: Application
    Filed: March 7, 2011
    Publication date: October 27, 2011
    Applicant: TDK Corporation
    Inventors: Takeo Kagami, Kosuke Tanaka, Shinji Hara, Takayasu Kanaya, Nobuyoshi Morizumi
  • Publication number: 20110157746
    Abstract: A perpendicular magnetic write head includes: a magnetic pole; a pair of side shields on both sides, in a write-track width direction, of the magnetic pole with respective side gaps in between; a trailing shield on a trailing side of the magnetic pole and the pair of side shields with a trailing gap in between. Each of the magnetic pole, the side shield, the trailing shield, the side gap, and the trailing gap has an end face exposed on an air bearing surface. The trailing gap has a first regional part and a second regional part. The first regional part separates a trailing edge of the magnetic pole from the trailing shield, and the second regional part separates the pair of side shields from the trailing shield. All or a part of the second regional part has a thickness larger than a thickness of the first regional part.
    Type: Application
    Filed: December 30, 2009
    Publication date: June 30, 2011
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Katsuki Kurihara, Kenkichi Anagawa, Takeo Kagami
  • Patent number: 7950135
    Abstract: A manufacturing method of an MR element in which current flows in a direction perpendicular to layer planes, includes a step of forming on a lower electrode layer an MR multi-layered structure with side surfaces substantially perpendicular to the layer lamination plane, a step of forming a first insulation layer on at least the side surfaces of the formed MR multi-layered structure, a step of forming a second insulation layer and a magnetic domain control bias layer on the lower electrode layer, and a step of forming an upper electrode layer on the MR multi-layered structure and the magnetic domain control bias layer.
    Type: Grant
    Filed: May 31, 2007
    Date of Patent: May 31, 2011
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Takayasu Kanaya
  • Patent number: 7916430
    Abstract: A thin-film magnetic head includes a lower magnetic shield layer, an MR multi-layered structure formed on the lower magnetic shield layer so that current flows in a direction perpendicular to surfaces of laminated layers, an upper magnetic shield layer formed on the MR multi-layered structure, and an additional lower magnetic shield layer directly laminated on the lower magnetic shield layer outside both side ends in a track-width direction of the MR multi-layered structure. The additional lower magnetic shield layer is directly contacted with both side surfaces in a track-width direction of the MR multi-layered structure. A top surface of the additional lower magnetic shield layer is positioned higher in height than a top surface of the lower magnetic shield layer in a region where the MR multi-layered structure is formed.
    Type: Grant
    Filed: August 9, 2007
    Date of Patent: March 29, 2011
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Takayasu Kanaya
  • Patent number: 7898775
    Abstract: An MR element includes a free layer whose direction of magnetization changes in response to an external magnetic field. Two bias magnetic field applying layers are disposed adjacent to two side surfaces of the MR element. Each bias magnetic field applying layer includes a nonmagnetic intermediate layer, and a first magnetic layer and a second magnetic layer disposed to sandwich the intermediate layer. The first and second magnetic layers are antiferromagnetically exchange-coupled to each other through RKKY interaction.
    Type: Grant
    Filed: July 13, 2007
    Date of Patent: March 1, 2011
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Shinji Hara, Takayasu Kanaya, Takeo Kagami
  • Patent number: 7876537
    Abstract: An MR element incorporates a layered structure. The layered structure includes: a spacer layer having a first surface and a second surface that face toward opposite directions; a free layer disposed adjacent to the first surface of the spacer layer and having a direction of magnetization that changes in response to a signal magnetic field; and a pinned layer disposed adjacent to the second surface of the spacer layer and having a fixed direction of magnetization. The spacer layer is a layer at least part of which is made of a material other than a conductor, and the spacer layer intercepts the passage of currents or limits the passage of currents as compared with a layer entirely made of a conductor. The MR element further incorporates a conductive film that is disposed on the peripheral surface of the layered structure and allows conduction between the free layer and the pinned layer.
    Type: Grant
    Filed: April 25, 2007
    Date of Patent: January 25, 2011
    Assignee: TDK Corporation
    Inventors: Takumi Uesugi, Tetsuro Sasaki, Takeo Kagami, Kei Hirata
  • Patent number: 7864489
    Abstract: Provided is a thin-film magnetic head in which a noise due to the voltage potential difference between the read head element and the protective coat surface is suppressed. The thin-film magnetic head comprises: a read head element, one end surface of the read head element reaching an head end surface on the ABS side; a protective coat formed on the head end surface in such a way to cover at least the one end surface of the read head element; and at least one antistatic means for preventing the protective coat from being electrostatically charged, formed on/above the element formation surface, one end surface of the at least one antistatic means reaching the head end surface, the protective coat covering a portion, not the whole, of the one end surface of the at least one antistatic means on the head end surface.
    Type: Grant
    Filed: February 26, 2007
    Date of Patent: January 4, 2011
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Takeo Kagami, Takumi Uesugi, Tetsuro Sasaki
  • Publication number: 20100302680
    Abstract: A perpendicular magnetic write head includes: a magnetic pole having an end face on an air bearing surface; and side shield layers each having an end face on the air bearing surface, and arranged on both sides, in a write track width direction, of the magnetic pole with a side gap in between. The end face of the magnetic pole has a geometry in which a width at a trailing edge is larger than a width at a leading edge. Relationship D1<D2, D1<D3, and D3?D2 are satisfied in the air bearing surface, where D1 is a gap length of the side gap at the trailing edge, D2 is a gap length of the side gap at the leading edge, and D3 is a gap length of the side gap at any position between the trailing edge and the leading edge.
    Type: Application
    Filed: June 1, 2009
    Publication date: December 2, 2010
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Takeo Kagami, Tatsuhiro Nojima, Hisayoshi Watanabe, Michitaka Nishiyama