Patents by Inventor Hironobu Matsuzawa

Hironobu Matsuzawa 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: 8147994
    Abstract: A layered structure includes an amorphous Ta layer, a metallic oxide layer formed from zinc oxide (ZnO) or magnesium oxide (MgO) on the Ta layer, and a FePt magnetic layer formed on the metallic oxide layer. Therefore, an L10 structural FePt ordered alloy is obtained at a temperature of 300° C. or lower.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: April 3, 2012
    Assignee: TDK Corporation
    Inventors: Hironobu Matsuzawa, Tsutomu Chou
  • Publication number: 20120002330
    Abstract: An MR element includes a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer disposed between the first and second ferromagnetic layers. The spacer layer includes a nonmagnetic metal layer, a first oxide semiconductor layer, and a second oxide semiconductor layer that are stacked in this order. The nonmagnetic metal layer is made of Cu, and has a thickness in the range of 0.3 to 1.5 nm. The first oxide semiconductor layer is made of a Ga oxide semiconductor, and has a thickness in the range of 0.5 to 2.0 nm. The second oxide semiconductor layer is made of a Zn oxide semiconductor, and has a thickness in the range of 0.1 to 1.0 nm.
    Type: Application
    Filed: June 30, 2010
    Publication date: January 5, 2012
    Applicant: TDK CORPORATION
    Inventors: Hironobu MATSUZAWA, Yoshihiro Tsuchiya
  • Patent number: 8029853
    Abstract: The inventive fabrication process for magnetoresistive devices (CPP-GMR devices) involves the formation of a zinc oxide or ZnO layer that provides the intermediate layer of a spacer layer, comprising Zn film formation operation for forming a zinc or Zn layer and Zn film oxidization operation for oxidizing the zinc film after the Zn film formation operation. The Zn film formation operation is implemented such that after a multilayer substrate having a multilayer structure before the formation of the Zn film is cooled down to the temperature range of ?140° C. to ?60° C., the formation of the Zn film is set off, and the Zn film oxidization operation is implemented such that after the completion of the Zn film oxidization operation, oxidization treatment is set off at the substrate temperature range of ?120° C. to ?40° C. Thus, excelling in both flatness and crystallizability, the ZnO layer makes sure the device has high MR ratios, and can further have an area resistivity AR best suited for the device.
    Type: Grant
    Filed: November 20, 2008
    Date of Patent: October 4, 2011
    Assignee: TDK Corporation
    Inventors: Hironobu Matsuzawa, Tsutomu Chou, Yoshihiro Tsuchiya, Shinji Hara
  • Patent number: 8031444
    Abstract: The semiconductor oxide layer that forms a part of the spacer layer in the inventive giant magnetoresistive device (CPP-GMR device) is composed of zinc oxide of wurtzite structure that is doped with a dopant given by at least one metal element selected from the group consisting of Zn, Ge, V, and Cr in a content of 0.05 to 0.90 at %: there is the advantage obtained that ever higher MR ratios are achievable while holding back an increase in the area resistivity AR.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: October 4, 2011
    Assignee: TDK Corporation
    Inventors: Tsutomu Chou, Tomohito Mizuno, Koji Shimazawa, Yoshihiro Tsuchiya, Shinji Hara, Hironobu Matsuzawa
  • Publication number: 20110051295
    Abstract: In an MR element of the present invention, an effect of an extremely-high MR ratio is obtained since a crystal structure of a CoFe magnetic layer in the vicinity of an interface with a spacer layer is formed as a close packed structure, such as an hcp structure and an fcc structure, and a total existing ratio of these crystal structures is 25% or more by an area ratio.
    Type: Application
    Filed: August 31, 2009
    Publication date: March 3, 2011
    Applicant: TDK CORPORATION
    Inventors: Shinji Hara, Tsutomu Chou, Yoshihiro Tsuchiya, Hironobu Matsuzawa
  • 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
  • Publication number: 20110007421
    Abstract: An MR element in a CPP-GMR structure includes a first ferromagnetic layer, a spacer layer that is epitaxially formed on the first ferromagnetic layer, a second ferromagnetic layer that is located on the spacer layer, and that is laminated with the first ferromagnetic layer to sandwich the spacer layer. A sense current flows along a lamination direction of the first and second ferromagnetic layers. Angle of magnetization directions of the first ferromagnetic layer and the second ferromagnetic layer relatively change due to an externally applied magnetic field.
    Type: Application
    Filed: July 10, 2009
    Publication date: January 13, 2011
    Applicant: TDK CORPORATION
    Inventors: Shinji Hara, Tsutomu Chou, Yoshihiro Tsuchiya, Hironobu Matsuzawa
  • Publication number: 20100232073
    Abstract: A thin film magnetic head includes a magnetoresistive effect (MR) laminated body that has the following structure: first and second magnetic layers in which the magnetization direction of at least one of the magnetic layers changes according to an external magnetic field; the first magnetic layer is provided at a lower side of a laminated direction; the second magnetic layer is provided at an upper side of the laminated direction; a non-magnetic intermediate layer made of ZnO sandwiched between the first and the second magnetic layers; a first intermediate interface layer is provided at the interface between the first magnetic layer and the non-magnetic intermediate layer; and a second intermediate interface layer is provided at the interface between the non-magnetic intermediate layer and the second magnetic layer. At least the first intermediate interface layer contains Ag and Zn, or Au and Zn.
    Type: Application
    Filed: March 10, 2009
    Publication date: September 16, 2010
    Applicant: TDK CORPORATION
    Inventors: Tsutomu Chou, Shinji Hara, Yoshihiro Tsuchiya, Hironobu Matsuzawa
  • Publication number: 20100232066
    Abstract: A magneto-resistive effect (MR) element includes a first magnetic layer and a second magnetic layer in which a relative angle of magnetization directions of the first and second magnetic layers changes according to an external magnetic field; and a spacer layer that is provided between the first magnetic layer and the second magnetic layer. The spacer layer contains gallium nitride (GaN) as a main component.
    Type: Application
    Filed: March 10, 2009
    Publication date: September 16, 2010
    Applicant: TDK CORPORATION
    Inventors: Shinji Hara, Yoshihiro Tsuchiya, Tsutomu Chou, Hironobu Matsuzawa
  • Publication number: 20100214701
    Abstract: An MR element according to the present invention has the superior effects that further improve an MR ratio because a structure of a spacer layer 40 is configured of a certain three-layer structure with certain materials, and at least one of a first ferromagnetic layer 30 and a second ferromagnetic layer 50 contains a certain amount of an element selected from the group of nitrogen (N), carbon (C), and oxygen (O).
    Type: Application
    Filed: February 26, 2009
    Publication date: August 26, 2010
    Applicant: TDK CORPORATION
    Inventors: Yoshihiro Tsuchiya, Shinji Hara, Tsutomu Chou, Hironobu Matsuzawa
  • Publication number: 20100214696
    Abstract: A layered structure includes an amorphous Ta layer, a metallic oxide layer formed from zinc oxide (ZnO) or magnesium oxide (MgO) on the Ta layer, and a FePt magnetic layer formed on the metallic oxide layer. Therefore, an L10 structural FePt ordered alloy is obtained at a temperature of 300° C. or lower.
    Type: Application
    Filed: February 26, 2009
    Publication date: August 26, 2010
    Applicant: TDK CORPORATION
    Inventors: Hironobu Matsuzawa, Tsutomu Chou
  • Publication number: 20100149689
    Abstract: A thin film magnetic head includes a magnetoresistance (MR) layered body that has first and second magnetic layers whose magnetization direction are changed according to an external magnetic field, a nonmagnetic middle layer and where the first magnetic layer, the nonmagnetic middle layer and the second magnetic layer are disposed in a manner of facing each other in respective order, first and second shield layers that are disposed in a manner of sandwiching the MR-stack in the film surface orthogonal direction of the MR-stack facing the first magnetic layer and the second magnetic layer, respectively, and that also serve as an electrode for applying a sense current to the film surface orthogonal direction of the MR-stack; and a bias magnetic field application means that is disposed on an opposite surface of an air bearing surface (ABS) of the MR-stack, and that applies a bias magnetic field to the MR-stack in the direction orthogonal to the ABS.
    Type: Application
    Filed: December 11, 2008
    Publication date: June 17, 2010
    Applicant: TDK CORPORATION
    Inventors: Yoshihiro Tsuchiya, Tsutomu Chou, Daisuke Miyauchi, Shinji Hara, Takahiko Machita, Hironobu Matsuzawa
  • Publication number: 20100124617
    Abstract: The inventive fabrication process for magnetoresistive devices (CPP-GMR devices) involves the formation of a zinc oxide or ZnO layer that provides the intermediate layer of a spacer layer, comprising Zn film formation operation for forming a zinc or Zn layer and Zn film oxidization operation for oxidizing the zinc film after the Zn film formation operation. The Zn film formation operation is implemented such that after a multilayer substrate having a multilayer structure before the formation of the Zn film is cooled down to the temperature range of ?140° C. to ?60° C., the formation of the Zn film is set off, and the Zn film oxidization operation is implemented such that after the completion of the Zn film oxidization operation, oxidization treatment is set off at the substrate temperature range of ?120° C. to ?40° C. Thus, excelling in both flatness and crystallizability, the ZnO layer makes sure the device has high MR ratios, and can further have an area resistivity AR best suited for the device.
    Type: Application
    Filed: November 20, 2008
    Publication date: May 20, 2010
    Applicant: TDK CORPORATION
    Inventors: Hironobu Matsuzawa, Tsutomu Chou, Yoshihiro Tsuchiya, Shinji Hara
  • Publication number: 20100097722
    Abstract: The semiconductor oxide layer that forms a part of the spacer layer in the inventive giant magnetoresistive device (CPP-GMR device) is composed of zinc oxide of wurtzite structure that is doped with a dopant given by at least one metal element selected from the group consisting of Zn, Ge, V, and Cr in a content of 0.05 to 0.90 at %: there is the advantage obtained that ever higher MR ratios are achievable while holding back an increase in the area resistivity AR.
    Type: Application
    Filed: October 21, 2008
    Publication date: April 22, 2010
    Applicant: TDK CORPORATION
    Inventors: Tsutomu Chou, Tomohito Mizuno, Koji Shimazawa, Yoshihiro Tsuchiya, Shinji Hara, Hironobu Matsuzawa
  • 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: 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: 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