Patents by Inventor Toshiyuki Ayukawa

Toshiyuki Ayukawa 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: 9389286
    Abstract: A magnetic sensor includes an MR element and a bias field generation unit. The MR element includes a magnetization pinned layer having a magnetization pinned in a direction parallel to an X direction, a free layer having a magnetization that varies depending on an X-direction component of an external magnetic field, and a nonmagnetic layer interposed between the magnetization pinned layer and the free layer. The magnetization pinned layer, the nonmagnetic layer and the free layer are stacked to be adjacent in a Y direction. The free layer receives an interlayer coupling magnetic field in a direction parallel to the X direction resulting from the magnetization pinned layer. The bias field generation unit applies a bias magnetic field to the free layer. The bias magnetic field includes a first component in a direction opposite to that of the interlayer coupling magnetic field and a second component in a Z direction.
    Type: Grant
    Filed: February 25, 2014
    Date of Patent: July 12, 2016
    Assignee: TDK CORPORATION
    Inventors: Hiroshi Yamazaki, Yoshiyuki Mizoguchi, Satoshi Abe, Homare Tokida, Toshiyuki Ayukawa
  • Publication number: 20140292322
    Abstract: A magnetic sensor includes an MR element and a bias field generation unit. The MR element includes a magnetization pinned layer having a magnetization pinned in a direction parallel to an X direction, a free layer having a magnetization that varies depending on an X-direction component of an external magnetic field, and a nonmagnetic layer interposed between the magnetization pinned layer and the free layer. The magnetization pinned layer, the nonmagnetic layer and the free layer are stacked to be adjacent in a Y direction. The free layer receives an interlayer coupling magnetic field in a direction parallel to the X direction resulting from the magnetization pinned layer. The bias field generation unit applies a bias magnetic field to the free layer. The bias magnetic field includes a first component in a direction opposite to that of the interlayer coupling magnetic field and a second component in a Z direction.
    Type: Application
    Filed: February 25, 2014
    Publication date: October 2, 2014
    Applicant: TDK CORPORATION
    Inventors: Hiroshi YAMAZAKI, Yoshiyuki MIZOGUCHI, Satoshi ABE, Homare TOKIDA, Toshiyuki AYUKAWA
  • Patent number: 8310791
    Abstract: A magnetoresistive effect element is structured in the manner that the antiferromagnetic layer interposed between the upper and lower shields is eliminated and the antiferromagnetic layer is positioned in a so-called shield layer. Therefore, it is realized to solve a pin reversal problem and to allow narrower tracks and narrower read gaps.
    Type: Grant
    Filed: March 13, 2009
    Date of Patent: November 13, 2012
    Assignee: TDK Corporation
    Inventors: Takahiko Machita, Tomohito Mizuno, Koji Shimazawa, Tsutomu Chou, Daisuke Miyauchi, Yoshihiro Tsuchiya, Shinji Hara, Toshiyuki Ayukawa
  • Patent number: 8213272
    Abstract: A waveguide is provided, in which the optical coupling efficiency to a light source is sufficiently high, and the light-emitting spot center is stably provided at the intended position. The waveguide comprises a multilayered structure in which refractive indexes of layers having a surface contact with each other are different from each other. The multilayered structure is divided into a plurality of groups, and the length from the light-receiving end surface to the light-emitting end surface of one group is different from that of the neighboring group, and the protruded light-emitting end surface of the first group defined as a group that has the largest length includes a center of the light-emitting spot. In this waveguide, the state in which the light-emitting spot center is positioned within the light-emitting end surface does not easily be changed, even when the light-receiving spot center within the light-receiving end surface is rather displaced.
    Type: Grant
    Filed: June 11, 2009
    Date of Patent: July 3, 2012
    Assignee: TDK Corporation
    Inventors: Seiichi Takayama, Satoshi Tomikawa, Toshiyuki Ayukawa, Daisuke Miyauchi, Koji Shimazawa
  • Patent number: 8149546
    Abstract: A magnetic field detecting element comprises a stack including upper and lower magnetic layers, and a non-magnetic intermediate layer sandwiched therebetween, wherein magnetization of the magnetic layers changes in accordance with an external magnetic field; upper and lower shield electrode layers sandwiching the stack in a direction of stacking, wherein the upper and lower shield electrode layers supply sense current in the direction of stacking, and magnetically shield the stack; a bias magnetic layer provided on a surface of the stack opposite to an air bearing surface, and wherein the bias magnetic layer applies a bias magnetic field to the upper and lower magnetic layers in a direction perpendicular to the air bearing surface; and insulating layers provided on both sides of the stack in a track width direction thereof, wherein the stack has a stepped portion formed at the non-magnetic intermediate layer.
    Type: Grant
    Filed: October 26, 2007
    Date of Patent: April 3, 2012
    Assignee: TDK Corporation
    Inventors: Toshiyuki Ayukawa, Daisuke Miyauchi, Koji Shimazawa, Takahiko Machita
  • Patent number: 8094420
    Abstract: The invention provides a magnetoresistive device of the CCP (current perpendicular to plane) structure comprising a magnetoresistive unit sandwiched between soft magnetic shield layers with a current applied in the stacking direction. The magnetoresistive unit comprises a nonmagnetic intermediate layer sandwiched between ferromagnetic layers. A planar framework positions the soft magnetic shield layers and comprises a combination of a nonmagnetic gap layer with a bias magnetic field-applying layer constructed by repeating the stacking of a multilayer unit comprising a nonmagnetic underlay layer and a high coercive material layer. The nonmagnetic gap layer is designed and located such that a magnetic flux given out of the bias magnetic field-applying layer is efficiently directed along a closed magnetic path around the framework to form a single domain of magnetization.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: January 10, 2012
    Assignee: TDK Corporation
    Inventors: Toshiyuki Ayukawa, Takahiko Machita, Daisuke Miyauchi, Tsutomu Chou, Koji Shimazawa, Shinji Hara, Tomohito Mizuno, Yoshihiro Tsuchiya
  • Patent number: 8009392
    Abstract: Foundation layers of a thin film magnetic head are disposed between insulating layers and bias magnetic field application layers, and are configured of Cr or Cr alloy. The insulating layers are configured of a Si oxide such that the Si content of the Si oxide is in the range of 30˜56 at % (atom %) and that the atom ratio of oxygen to Si (O/Si) is in the range of 0.8˜1.3. With the configuration, the occurrence rate of noise is reduced.
    Type: Grant
    Filed: January 13, 2009
    Date of Patent: August 30, 2011
    Assignee: TDK Corporation
    Inventors: Takayasu Kanaya, Kei Hirata, Yohei Koyanagi, Seiichi Takayama, Shinji Hara, Toshiyuki Ayukawa
  • Patent number: 7947188
    Abstract: A method for manufacturing a thin film magnetic head includes a step for forming an MR layered body; a step for forming a first sacrificial layer made of material removable by wet etching, and subsequently, forming a cap layer on the upper surface of the first sacrificial layer; further, a step for patterning the MR layered body and the cap layer and then filling part of the removed areas of the MR layered body and the cap layer with a bias magnetic layer and the remaining with insulating layers; a step for removing the cap layer by dry etching and, subsequently, removing the first sacrificial layer by wet etching; and a step for forming a second shield layer above the MR layered body and the bias magnetic layer.
    Type: Grant
    Filed: December 30, 2008
    Date of Patent: May 24, 2011
    Assignee: TDK Corporation
    Inventors: Toshiyuki Ayukawa, Shinji Hara, Daisuke Miyauchi, Takahiko Machita, Yoshihiro Tsuchiya
  • Patent number: 7881021
    Abstract: A magnetoresistive device with CPP structure, comprising a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed with said nonmagnetic intermediate layer interposed between them, wherein each of said first and second ferromagnetic layers comprises a sensor area joining to the nonmagnetic intermediate layer and a magnetization direction control area that extends further rearward from the position of the rear end of said nonmagnetic intermediate layer; a magnetization direction control multilayer arrangement is interposed at an area where the magnetization direction control area for said first ferromagnetic layer is opposite to the magnetization direction control area for said second ferromagnetic layer to produce magnetizations of the said first and second ferromagnetic layers which are antiparallel with each other; and said sensor area is provided at both width direction ends with biasing layers working such that the mutually antiparallel magnetiza
    Type: Grant
    Filed: January 30, 2008
    Date of Patent: February 1, 2011
    Assignee: TDK Corporation
    Inventors: Tsutomu Chou, Yoshihiro Tsuchiya, Daisuke Miyauchi, Takahiko Machita, Shinji Hara, Tomohito Mizuno, Hironobu Matsuzawa, Toshiyuki Ayukawa, Koji Shimazawa, Kiyoshi Noguchi
  • Patent number: 7855859
    Abstract: In an MR element, first and second ferromagnetic layers are antiferromagnetically coupled to each other through a spacer layer, and have magnetizations that are in opposite directions when no external magnetic field is applied thereto and that change directions in response to an external magnetic field. The spacer layer and the second ferromagnetic layer are stacked in this order on the first ferromagnetic layer. The first ferromagnetic layer includes a plurality of ferromagnetic material layers stacked, and an insertion layer made of a nonmagnetic material and inserted between respective two of the ferromagnetic material layers that are adjacent to each other along the direction in which the layers are stacked. The ferromagnetic material layers and the spacer layer each include a component whose crystal structure is a face-centered cubic structure.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: December 21, 2010
    Assignee: TDK Corporation
    Inventors: Shinji Hara, Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno, Tsuyoshi Ichiki, Toshiyuki Ayukawa
  • Publication number: 20100315736
    Abstract: A waveguide is provided, in which the optical coupling efficiency to a light source is sufficiently high, and the light-emitting spot center is stably provided at the intended position. The waveguide comprises a multilayered structure in which refractive indexes of layers having a surface contact with each other are different from each other. The multilayered structure is divided into a plurality of groups, and the length from the light-receiving end surface to the light-emitting end surface of one group is different from that of the neighboring group, and the protruded light-emitting end surface of the first group defined as a group that has the largest length includes a center of the light-emitting spot. In this waveguide, the state in which the light-emitting spot center is positioned within the light-emitting end surface does not easily be changed, even when the light-receiving spot center within the light-receiving end surface is rather displaced.
    Type: Application
    Filed: June 11, 2009
    Publication date: December 16, 2010
    Applicant: TDK Corporation
    Inventors: Seiichi Takayama, Satoshi Tomikawa, Toshiyuki Ayukawa, Daisuke Miyauchi, Koji Shimazawa
  • Publication number: 20100232074
    Abstract: A magnetoresistive effect element is structured in the manner that the antiferromagnetic layer interposed between the upper and lower shields is eliminated and the antiferromagnetic layer is positioned in a so-called shield layer. Therefore, it is realized to solve a pin reversal problem and to allow narrower tracks and narrower read gaps.
    Type: Application
    Filed: March 13, 2009
    Publication date: September 16, 2010
    Applicant: TDK CORPORATION
    Inventors: Takahiko Machita, Tomohito Mizuno, Koji Shimazawa, Tsutomu Chou, Daisuke Miyauchi, Yoshihiro Tsuchiya, Shinji Hara, Toshiyuki Ayukawa
  • Publication number: 20100177440
    Abstract: Foundation layers of a thin film magnetic head are disposed between insulating layers and bias magnetic field application layers, and are configured of Cr or Cr alloy. The insulating layers are configured of a Si oxide such that the Si content of the Si oxide is in the range of 30˜56 at % (atom %) and that the atom ratio of oxygen to Si (O/Si) is in the range of 0.8˜1.3. With the configuration, the occurrence rate of noise is reduced.
    Type: Application
    Filed: January 13, 2009
    Publication date: July 15, 2010
    Applicant: TDK CORPORATION
    Inventors: Takayasu Kanaya, Kei Hirata, Yohei Koyanagi, Seiichi Takayama, Shinji Hara, Toshiyuki Ayukawa
  • Publication number: 20100163519
    Abstract: A method for manufacturing a thin film magnetic head includes a step for forming an MR layered body; a step for forming a first sacrificial layer made of material removable by wet etching, and subsequently, forming a cap layer on the upper surface of the first sacrificial layer; further, a step for patterning the MR layered body and the cap layer and then filling part of the removed areas of the MR layered body and the cap layer with a bias magnetic layer and the remaining with insulating layers; a step for removing the cap layer by dry etching and, subsequently, removing the first sacrificial layer by wet etching; and a step for forming a second shield layer above the MR layered body and the bias magnetic layer.
    Type: Application
    Filed: December 30, 2008
    Publication date: July 1, 2010
    Applicant: TDK CORPORATION
    Inventors: Toshiyuki Ayukawa, Shinji Hara, Daisuke Miyauchi, Takahiko Machita, Yoshihiro Tsuchiya
  • Publication number: 20100103563
    Abstract: A magnetoresistive element includes first and second shield portions and an MR stack. Each of the first and second shield portions includes a shield bias magnetic field applying layer, and a closed-magnetic-path-forming portion that forms a closed magnetic path in conjunction of the shield bias magnetic field applying layer. The closed-magnetic-path-forming portion includes a single magnetic domain portion. The MR stack is sandwiched between the respective single magnetic domain portions of the first and second shield portions. The closed-magnetic-path-forming portion includes a magnetic-path-expanding portion that forms a magnetic path, the magnetic path being a portion of the closed magnetic path and located between the shield bias magnetic field applying layer and the single magnetic domain portion. The magnetic-path-expanding portion has two end portions located at both ends of the magnetic path, and a middle portion located between the two end portions.
    Type: Application
    Filed: October 29, 2008
    Publication date: April 29, 2010
    Applicant: TDK CORPORATION
    Inventors: Takahiko Machita, Daisuke Miyauchi, Tsutomu Chou, Toshiyuki Ayukawa
  • Publication number: 20090303640
    Abstract: A magneto resistance effect element includes a first magnetic layer, a second magnetic layer and a spacer layer interposed between the first and second magnetic layers. The magneto resistance effect element is configured to allow sense current to flow in a direction that is perpendicular to film planes of the first magnetic layer, the second magnetic layer and the spacer layer so that a relative angle between a magnetization direction of the first magnetic layer and a magnetization direction of the second magnetic layer varies depending on an external magnetic field. The present invention aims at providing a magneto resistance effect element which ensures high resistance to sense current, while limiting the influence of the current limiting layer on the magnetic layer, and which thereby achieves a high magneto resistance ratio.
    Type: Application
    Filed: April 25, 2008
    Publication date: December 10, 2009
    Applicant: TDK CORPORATION
    Inventors: Tomohito Mizuno, Koji Shimazawa, Yoshihiro Tsuchiya, Daisuke Miyauchi, Takahiko Machita, Shinji Hara, Tsutomu Chou, Hironobu Matsuzawa, Toshiyuki Ayukawa, Tsuyoshi Ichiki
  • Publication number: 20090290264
    Abstract: The invention provides a magnetoresistive device of the CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first, substantially soft magnetic shield layer positioned below and a second, substantially soft magnetic shield layer positioned above, which are located and formed such that the magnetoresistive effect is sandwiched between them from above and below, with a sense current applied in the stacking direction. The magnetoresistive unit comprises a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed such that said nonmagnetic intermediate layer is sandwiched between them. At least one of the first shield layer positioned below and the second shield layer positioned above is configured in a framework form having a planar shape (X-Y plane) defined by the width and length directions of the device.
    Type: Application
    Filed: May 23, 2008
    Publication date: November 26, 2009
    Applicant: TDK CORPORATION
    Inventors: Toshiyuki Ayukawa, Takahiko Machita, Daisuke Miyauchi, Tsutomu Chou, Koji Shimazawa, Shinji Hara, Tomohito Mizuno, Yoshihiro Tsuchiya
  • Publication number: 20090190270
    Abstract: The invention provides a magnetoresistive device with the CPP (current perpendicular to plane) structure, comprising a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed with said nonmagnetic intermediate layer interposed between them, with a sense current applied in the stacking direction, wherein each of said first and second ferromagnetic layers comprises a sensor area joining to the nonmagnetic intermediate layer near a medium opposite plane and a magnetization direction control area that extends further rearward (toward the depth side) from the position of the rear end of said nonmagnetic intermediate layer; a magnetization direction control multilayer arrangement is interposed at an area where the magnetization direction control area for said first ferromagnetic layer is opposite to the magnetization direction control area for said second ferromagnetic layer in such a way that the magnetizations of the said first and second ferromagnetic l
    Type: Application
    Filed: January 30, 2008
    Publication date: July 30, 2009
    Applicant: TDK Corporation
    Inventors: Tsutomu Chou, Yoshihiro Tsuchiya, Daisuke Miyauchi, Takahiko Machita, Shinji Hara, Tomohito Mizuno, Hironobu Matsuzawa, Toshiyuki Ayukawa, Koji Shimazawa, Kiyoshi Noguchi
  • Publication number: 20090168264
    Abstract: In an MR element, first and second ferromagnetic layers are antiferromagnetically coupled to each other through a spacer layer, and have magnetizations that are in opposite directions when no external magnetic field is applied thereto and that change directions in response to an external magnetic field. The spacer layer and the second ferromagnetic layer are stacked in this order on the first ferromagnetic layer. The first ferromagnetic layer includes a plurality of ferromagnetic material layers stacked, and an insertion layer made of a nonmagnetic material and inserted between respective two of the ferromagnetic material layers that are adjacent to each other along the direction in which the layers are stacked. The ferromagnetic material layers and the spacer layer each include a component whose crystal structure is a face-centered cubic structure.
    Type: Application
    Filed: December 27, 2007
    Publication date: July 2, 2009
    Applicant: TDK CORPORATION
    Inventors: Shinji Hara, Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno, Tsuyoshi Ichiki, Toshiyuki Ayukawa
  • Publication number: 20090128965
    Abstract: A magnetic field detecting element has a stack which includes a NiCr layer, a first magnetic layer whose magnetization direction varies in accordance with an external magnetic field, a non-magnetic spacer layer, and a second magnetic layer whose magnetization direction varies in accordance with the external magnetic field, said NiCr layer, said first magnetic layer, said spacer layer and said second magnetic layer being disposed in this order and being arranged in contact with each other, wherein a sense current is adapted to flow in a direction that is perpendicular to a film surface of said stack; and a bias magnetic layer which is disposed on a side of said stack, said side being opposite to an air bearing surface of said stack, wherein said bias magnetic layer is adapted to apply a bias magnetic field to said stack in a direction that is perpendicular to said air bearing surface.
    Type: Application
    Filed: November 15, 2007
    Publication date: May 21, 2009
    Inventors: Tomohito MIZUNO, Yoshihiro TSUCHIYA, Shinji HARA, Koji SHIMAZAWA, Daisuke MIYAUCHI, Takahiko MACHITA, Tsutomu CHOU, Toshiyuki AYUKAWA, Hironobu MATSUZAWA, Tsuyoshi ICHIKI