Patents by Inventor Tohru Oikawa

Tohru Oikawa 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: 11495735
    Abstract: A spin-current magnetization rotational element includes: a ferromagnetic metal layer; and a spin-orbit torque wiring that extends in a first direction intersecting a stacking direction of the ferromagnetic metal layer and is bonded to the ferromagnetic metal layer. A direction of a spin injected into the ferromagnetic metal layer from the spin-orbit torque wiring intersects a magnetization direction of the ferromagnetic metal layer. The ferromagnetic metal layer has shape anisotropy and has a demagnetizing field distribution caused by the shape anisotropy. The demagnetizing field distribution generates an easy magnetization rotational direction in which the magnetization of the ferromagnetic metal layer is most easily reversed. The easy magnetization rotational direction intersects the first direction in a plan view seen from the stacking direction.
    Type: Grant
    Filed: July 25, 2017
    Date of Patent: November 8, 2022
    Assignee: TDK CORPORATION
    Inventors: Tatsuo Shibata, Tomoyuki Sasaki, Tohru Oikawa
  • Publication number: 20220158082
    Abstract: A method for producing a spin current magnetization rotational element includes a stacking step of stacking, on one surface of a substrate, a magnetoresistance effect element having a first ferromagnetic metal layer having a fixed magnetization direction, a second ferromagnetic metal layer having a variable magnetization direction, and a non-magnetic layer sandwiched between the first ferromagnetic metal layer and the second ferromagnetic metal layer, and spin-orbit torque wiring which extends in a first direction, wherein an inclined surface non-parallel to the first direction is formed on at least a part of a surface of the spin-orbit torque wiring.
    Type: Application
    Filed: November 15, 2021
    Publication date: May 19, 2022
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Tatsuo SHIBATA, Tohru OIKAWA
  • Patent number: 11211548
    Abstract: This spin current magnetization reversal element includes a magnetoresistance effect element having a first ferromagnetic metal layer having a fixed magnetization direction, a second ferromagnetic metal layer having a variable magnetization direction, and a non-magnetic layer sandwiched between the first ferromagnetic metal layer and the second ferromagnetic metal layer, and spin-orbit torque wiring which extends in a first direction that intersects the stacking direction of the magnetoresistance effect element, and contacts the surface of the magnetoresistance elect element on the side facing the second ferromagnetic metal layer, wherein at least one surface of the second ferromagnetic metal layer in the stacking direction has an inclined surface that is inclined in the first direction, and the direction of magnetization of the second ferromagnetic metal layer is inclined due to the inclined surface.
    Type: Grant
    Filed: July 19, 2019
    Date of Patent: December 28, 2021
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Tatsuo Shibata, Tohru Oikawa
  • Patent number: 11107615
    Abstract: A magnetization rotational element includes a ferromagnetic metal layer, and a spin-orbit torque wiring extending in a first direction intersecting a lamination direction of the ferromagnetic metal layer and having the ferromagnetic metal layer positioned on one surface thereof, in which a direction of spin injected from the spin-orbit torque wiring into the ferromagnetic metal layer intersects a magnetization direction of the ferromagnetic metal layer, and a damping constant of the ferromagnetic metal layer is larger than 0.01.
    Type: Grant
    Filed: February 22, 2018
    Date of Patent: August 31, 2021
    Assignee: TDK CORPORATION
    Inventors: Tohru Oikawa, Tomoyuki Sasaki, Yohei Shiokawa, Tatsuo Shibata
  • Patent number: 10892401
    Abstract: This spin current magnetization rotational element includes a second ferromagnetic metal layer 1 having a variable magnetization orientation, and spin-orbit torque wiring 2, which extends in a direction that intersects a direction perpendicular to the surface of the second ferromagnetic metal layer 1, and is connected to the second ferromagnetic metal layer 1, wherein the spin resistance of a connection portion of the spin-orbit torque wiring layer 2 that is connected to the second ferromagnetic metal layer 1 is larger than the spin resistance of the second ferromagnetic metal layer 1.
    Type: Grant
    Filed: September 18, 2019
    Date of Patent: January 12, 2021
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Tohru Oikawa
  • Publication number: 20200168383
    Abstract: A magnetization rotational element includes a ferromagnetic metal layer, and a spin-orbit torque wiring extending in a first direction intersecting a lamination direction of the ferromagnetic metal layer and having the ferromagnetic metal layer positioned on one surface thereof, in which a direction of spin injected from the spin-orbit torque wiring into the ferromagnetic metal layer intersects a magnetization direction of the ferromagnetic metal layer, and a damping constant of the ferromagnetic metal layer is larger than 0.01.
    Type: Application
    Filed: February 22, 2018
    Publication date: May 28, 2020
    Applicant: TDK CORPORATION
    Inventors: Tohru OIKAWA, Tomoyuki SASAKI, Yohei SHIOKAWA, Tatsuo SHIBATA
  • Patent number: 10636466
    Abstract: A spin current assisted magnetoresistance effect device includes: a spin current assisted magnetoresistance effect element including a magnetoresistance effect element part and a spin-orbit torque wiring; and a controller electrically connected to the spin current assisted magnetoresistance effect element. In a portion in which the magnetoresistance effect element part and the spin-orbit torque wiring are bonded, an STT inversion current flowing through the magnetoresistance effect element part and an SOT inversion current flowing through the spin-orbit torque wiring merge or are divided, and the controller is configured to be capable of performing control for applying the STT inversion current to the spin current assisted magnetoresistance effect element at the same time as an application of the SOT inversion current or a time application of the SOT inversion current.
    Type: Grant
    Filed: November 15, 2019
    Date of Patent: April 28, 2020
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Tohru Oikawa
  • Patent number: 10593867
    Abstract: A spin current magnetization rotational element includes: a first ferromagnetic metal layer having a variable magnetization direction; and a spin orbital torque wiring which is joined to the first ferromagnetic metal layer and extends in a direction crossing a direction perpendicular to a plane of the first ferromagnetic metal layer, wherein the spin orbital torque wiring is constituted of a non-magnetic material composed of elements of two or more kinds and a compositional proportion of the non-magnetic material has a non-uniform distribution between a first surface joined to the first ferromagnetic metal layer and a second surface located on a side opposite to the first surface.
    Type: Grant
    Filed: November 14, 2017
    Date of Patent: March 17, 2020
    Assignee: TDK CORPORATION
    Inventors: Yohei Shiokawa, Tomoyuki Sasaki, Tohru Oikawa
  • Publication number: 20200082964
    Abstract: A composite magnetic body with high permeability and low magnetic loss in a high-frequency region of a gigahertz band; and a high-frequency electronic component using the same, the electronic component being compact and having low-insertion loss. This composite magnetic body has a high permeability and a low magnetic loss especially in a high-frequency region of a gigahertz band, and is provided with: a plurality of magnetic nanowires 361-363 aligned so as not to cross each other; and insulators 365-367 that electrically insulate the plurality of magnetic nanowires 361-363.
    Type: Application
    Filed: March 30, 2018
    Publication date: March 12, 2020
    Applicant: TDK CORPORATION
    Inventors: Takeshi SAKAMOTO, Yoshihiro SHINKAI, Yu YONEZAWA, Hideharu MORO, Kensuke ARA, Tohru OIKAWA, Isao KANADA, Kenji HORINO, Kyung-Ku CHOI
  • Publication number: 20200082861
    Abstract: A spin current assisted magnetoresistance effect device includes: a spin current assisted magnetoresistance effect element including a magnetoresistance effect element part and a spin-orbit torque wiring; and a controller electrically connected to the spin current assisted magnetoresistance effect element. In a portion in which the magnetoresistance effect element part and the spin-orbit torque wiring are bonded, an STT inversion current flowing through the magnetoresistance effect element part and an SOT inversion current flowing through the spin-orbit torque wiring merge or are divided, and the controller is configured to be capable of performing control for applying the STT inversion current to the spin current assisted magnetoresistance effect element at the same time as an application of the SOT inversion current or a time application of the SOT inversion current.
    Type: Application
    Filed: November 15, 2019
    Publication date: March 12, 2020
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Tohru OIKAWA
  • Publication number: 20200035911
    Abstract: This spin current magnetization rotational element includes a second ferromagnetic metal layer 1 having a variable magnetization orientation, and spin-orbit torque wiring 2, which extends in a direction that intersects a direction perpendicular to the surface of the second ferromagnetic metal layer 1, and is connected to the second ferromagnetic metal layer 1, wherein the spin resistance of a connection portion of the spin-orbit torque wiring layer 2 that is connected to the second ferromagnetic metal layer 1 is larger than the spin resistance of the second ferromagnetic metal layer 1.
    Type: Application
    Filed: September 18, 2019
    Publication date: January 30, 2020
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Tohru OIKAWA
  • Patent number: 10497417
    Abstract: A spin current assisted magnetoresistance effect device includes: a spin current assisted magnetoresistance effect element including a magnetoresistance effect element part and a spin-orbit torque wiring; and a controller electrically connected to the spin current assisted magnetoresistance effect element. In a portion in which the magnetoresistance effect element part and the spin-orbit torque wiring are bonded, an STT inversion current flowing through the magnetoresistance effect element part and an SOT inversion current flowing through the spin-orbit torque wiring merge or are divided, and the controller is configured to be capable of performing control for applying the STT inversion current to the spin current assisted magnetoresistance effect element at the same time as an application of the SOT inversion current or a time application of the SOT inversion current.
    Type: Grant
    Filed: May 22, 2017
    Date of Patent: December 3, 2019
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Tohru Oikawa
  • Patent number: 10490731
    Abstract: This spin current magnetization rotational element includes a second ferromagnetic metal layer having a variable magnetization orientation, and spin-orbit torque wiring, which extends in a direction that intersects a direction perpendicular to the surface of the second ferromagnetic metal layer, and is connected to the second ferromagnetic metal layer, wherein the spin resistance of a connection portion of the spin-orbit torque wiring that is connected to the second ferromagnetic metal layer is larger than the spin resistance of the second ferromagnetic metal layer.
    Type: Grant
    Filed: November 25, 2016
    Date of Patent: November 26, 2019
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Tohru Oikawa
  • Publication number: 20190348598
    Abstract: This spin current magnetization reversal element includes a magnetoresistance effect element having a first ferromagnetic metal layer having a fixed magnetization direction, a second ferromagnetic metal layer having a variable magnetization direction, and a non-magnetic layer sandwiched between the first ferromagnetic metal layer and the second ferromagnetic metal layer, and spin-orbit torque wiring which extends in a first direction that intersects the stacking direction of the magnetoresistance effect element, and contacts the surface of the magnetoresistance elect element on the side facing the second ferromagnetic metal layer, wherein at least one surface of the second ferromagnetic metal layer in the stacking direction has an inclined surface that is inclined in the first direction, and the direction of magnetization of the second ferromagnetic metal layer is inclined due to the inclined surface.
    Type: Application
    Filed: July 19, 2019
    Publication date: November 14, 2019
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Tatsuo SHIBATA, Tohru OIKAWA
  • Patent number: 10418545
    Abstract: This spin current magnetization reversal element includes a magnetoresistance effect element having a first ferromagnetic metal layer having a fixed magnetization direction, a second ferromagnetic metal layer having a variable magnetization direction, and a non-magnetic layer sandwiched between the first ferromagnetic metal layer and the second ferromagnetic metal layer, and spin-orbit torque wiring which extends in a first direction that intersects the stacking direction of the magnetoresistance effect element, and contacts the surface of the magnetoresistance effect element on the side facing the second ferromagnetic metal layer, wherein at least one surface of the second ferromagnetic metal layer in the stacking direction has an inclined surface that is inclined in the first direction, and the direction of magnetization of the second ferromagnetic metal layer is inclined due to the inclined surface.
    Type: Grant
    Filed: July 5, 2017
    Date of Patent: September 17, 2019
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Tatsuo Shibata, Tohru Oikawa
  • Publication number: 20190147929
    Abstract: A spin current assisted magnetoresistance effect device includes: a spin current assisted magnetoresistance effect element including a magnetoresistance effect element part and a spin-orbit torque wiring; and a controller electrically connected to the spin current assisted magnetoresistance effect element. In a portion in which the magnetoresistance effect element part and the spin-orbit torque wiring are bonded, an STT inversion current flowing through the magnetoresistance effect element part and an SOT inversion current flowing through the spin-orbit torque wiring merge or are divided, and the controller is configured to be capable of performing control for applying the STT inversion current to the spin current assisted magnetoresistance effect element at the same time as an application of the SOT inversion current or a time application of the SOT inversion current.
    Type: Application
    Filed: May 22, 2017
    Publication date: May 16, 2019
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Tohru OIKAWA
  • Publication number: 20190058111
    Abstract: A spin-current magnetization rotational element includes: a ferromagnetic metal layer; and a spin-orbit torque wiring that extends in a first direction intersecting a stacking direction of the ferromagnetic metal layer and is bonded to the ferromagnetic metal layer. A direction of a spin injected into the ferromagnetic metal layer from the spin-orbit torque wiring intersects a magnetization direction of the ferromagnetic metal layer. The ferromagnetic metal layer has shape anisotropy and has a demagnetizing field distribution caused by the shape anisotropy. The demagnetizing field distribution generates an easy magnetization rotational direction in which the magnetization of the ferromagnetic metal layer is most easily reversed. The easy magnetization rotational direction intersects the first direction in a plan view seen from the stacking direction.
    Type: Application
    Filed: July 25, 2017
    Publication date: February 21, 2019
    Applicant: TDK CORPORATION
    Inventors: Tatsuo SHIBATA, Tomoyuki SASAKI, Tohru OIKAWA
  • Publication number: 20190051816
    Abstract: A spin current magnetization rotational element includes: a first ferromagnetic metal layer having a variable magnetization direction; and a spin orbital torque wiring which is joined to the first ferromagnetic metal layer and extends in a direction crossing a direction perpendicular to a plane of the first ferromagnetic metal layer, wherein the spin orbital torque wiring is constituted of a non-magnetic material composed of elements of two or more kinds and a compositional proportion of the non-magnetic material has a non-uniform distribution between a first surface joined to the first ferromagnetic metal layer and a second surface located on a side opposite to the first surface.
    Type: Application
    Filed: November 14, 2017
    Publication date: February 14, 2019
    Applicant: TDK CORPORATION
    Inventors: Yohei SHIOKAWA, Tomoyuki SASAKI, Tohru OIKAWA
  • Patent number: 10193061
    Abstract: A spin-orbit torque magnetization rotational element includes: a ferromagnetic metal layer, a magnetization direction of which is configured to be changed; a spin-orbit torque wiring bonded to the ferromagnetic metal layer; and an interfacial distortion supply layer bonded to a surface of the spin-orbit torque wiring on a side opposite to the ferromagnetic metal layer.
    Type: Grant
    Filed: October 25, 2017
    Date of Patent: January 29, 2019
    Assignee: TDK CORPORATION
    Inventors: Yohei Shiokawa, Tomoyuki Sasaki, Tohru Oikawa
  • Publication number: 20180351082
    Abstract: This spin current magnetization rotational element includes a second ferromagnetic metal layer having a variable magnetization orientation, and spin-orbit torque wiring, which extends in a direction that intersects a direction perpendicular to the surface of the second ferromagnetic metal layer, and is connected to the second ferromagnetic metal layer, wherein the spin resistance of a connection portion of the spin-orbit torque wiring that is connected to the second ferromagnetic metal layer is larger than the spin resistance of the second ferromagnetic metal layer.
    Type: Application
    Filed: November 25, 2016
    Publication date: December 6, 2018
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Tohru OIKAWA