Patents by Inventor Soichi Oikawa

Soichi 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: 10734053
    Abstract: According to one embodiment, a magnetic memory device includes a conductive member, a first magnetic layer, a second magnetic layer, and a first nonmagnetic layer. The conductive member includes a first layer. The first layer includes at least one selected from the group consisting of HfN having a NaCl structure, HfN having a fcc structure, and HfC having a NaCl structure. The first magnetic layer is separated from the first layer in a first direction. The second magnetic layer is provided between the first layer and the first magnetic layer. The first nonmagnetic layer is provided between the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: February 11, 2019
    Date of Patent: August 4, 2020
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Mizue Ishikawa, Yushi Kato, Soichi Oikawa, Hiroaki Yoda
  • Publication number: 20200168260
    Abstract: According to one embodiment, a magnetic memory device includes a conductive member, a first magnetic layer, a first counter magnetic layer, and a first nonmagnetic layer. The conductive member includes a first portion, a second portion, and a third portion between the first portion and the second portion. The first counter magnetic layer is provided between the third portion and the first magnetic layer in a first direction crossing a second direction. The second direction is from the first portion toward the second portion. The first nonmagnetic layer is provided between the first magnetic layer and the first counter magnetic layer. The third portion includes a first position, and a second position between the first position and the first counter magnetic layer in the first direction. A second concentration of boron at the second position is lower than a first concentration of boron at the first position.
    Type: Application
    Filed: November 27, 2019
    Publication date: May 28, 2020
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yushi KATO, Soichi OIKAWA, Hiroaki YODA
  • Publication number: 20200168790
    Abstract: According to one embodiment, a magnetic memory device includes a first magnetic region, a first counter magnetic region, and a first nonmagnetic region provided between the first magnetic region and the first counter magnetic region. The first magnetic region includes a first magnetic film, a second magnetic film, and an intermediate film. The first magnetic film is provided between the second magnetic film and the first nonmagnetic region. The intermediate film includes Ru and is provided between the first magnetic film and the second magnetic film. A distance along a first direction between the first magnetic film and the second magnetic film is not less than 1.8 nm and not more than 2.2 nm. The first direction is from the first counter magnetic region toward the first magnetic region.
    Type: Application
    Filed: November 27, 2019
    Publication date: May 28, 2020
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Soichi OIKAWA, Yushi KATO, Hiroaki YODA
  • Publication number: 20200058338
    Abstract: According to one embodiment, a magnetic memory device includes a conductive member, a first magnetic layer, a second magnetic layer, and a first nonmagnetic layer. The conductive member includes a first layer. The first layer includes at least one selected from the group consisting of HfN having a NaCl structure, HfN having a fcc structure, and HfC having a NaCl structure. The first magnetic layer is separated from the first layer in a first direction. The second magnetic layer is provided between the first layer and the first magnetic layer. The first nonmagnetic layer is provided between the first magnetic layer and the second magnetic layer.
    Type: Application
    Filed: February 11, 2019
    Publication date: February 20, 2020
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Mizue ISHIKAWA, Yushi KATO, Soichi OIKAWA, Hiroaki YODA
  • Patent number: 10490736
    Abstract: A magnetic memory according to an embodiment includes: first to third terminals; a nonmagnetic conductive layer including first to third regions, the second region being disposed between the first and third regions, the first region being electrically connected to the first terminal, and the third region being electrically connected to the second terminal; and a magnetoresistive element disposed to correspond to the second region, including a first magnetic layer electrically connected to the third terminal, a second magnetic layer disposed between the first magnetic layer and the second region, and a nonmagnetic layer disposed between the first and second magnetic layers, the conductive layer including at least one of an alloy including Ir and Ta, an alloy including Ir and V, an alloy including Au and V, an alloy including Au and Nb, or an alloy including Pt and V, each of the alloys having an fcc structure.
    Type: Grant
    Filed: March 6, 2018
    Date of Patent: November 26, 2019
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshiaki Saito, Tomoaki Inokuchi, Yushi Kato, Soichi Oikawa, Mizue Ishikawa, Hiroaki Yoda
  • Patent number: 10453513
    Abstract: According to one embodiment, a magnetic memory device includes a conductive layer, a first magnetic layer, a second magnetic layer, a first nonmagnetic layer, and a controller. The conductive layer includes first and second portions, and a third portion between the first and second portions. The conductive layer includes a first metal and boron. The first magnetic layer is separated from the third portion in a first direction crossing a second direction. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The controller supplies a current to the conductive layer. The first metal includes at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
    Type: Grant
    Filed: March 12, 2018
    Date of Patent: October 22, 2019
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yushi Kato, Yoshiaki Saito, Mizue Ishikawa, Soichi Oikawa, Hiroaki Yoda
  • Patent number: 10374150
    Abstract: According to one embodiment, a magnetic memory device includes a conductive layer, first and second magnetic layers, a first nonmagnetic layer and a controller. The conductive layer includes first and second portions, and a third portion positioned between the first and second portions. The conductive layer includes a first metal. The first magnetic layer is separated from the third portion. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The second magnetic layer has first and second lattice lengths. The first lattice length is longer than the second lattice length. The controller implements a first operation of supplying a first current to the conductive layer, and a second operation of supplying a second current to the conductive layer.
    Type: Grant
    Filed: February 26, 2018
    Date of Patent: August 6, 2019
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yushi Kato, Yoshiaki Saito, Soichi Oikawa, Mizue Ishikawa, Hiroaki Yoda
  • Patent number: 10360960
    Abstract: According to one embodiment, a magnetic memory device includes a conductive layer, a first magnetic layer, a second magnetic layer, a first nonmagnetic layer, and a controller. The conductive layer includes a first portion, a second portion, and a third portion between the first and second portions. The first magnetic layer is separated from the third portion. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The third portion includes a first region and a second region. The second region is provided between the first region and the second magnetic layer. The controller implements a first operation of supplying a first current to the conductive layer, and a second operation of supplying a second current to the conductive layer.
    Type: Grant
    Filed: September 11, 2017
    Date of Patent: July 23, 2019
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yushi Kato, Soichi Oikawa, Mizue Ishikawa, Yoshiaki Saito, Hiroaki Yoda
  • Patent number: 10262711
    Abstract: A magnetic memory of an embodiment includes: first through third terminals; a conductive layer including first through third portions, the first portion being located between the second and third portions, the second and third portions being electrically connected to the first and second terminals respectively; and a magnetoresistive element including: a first magnetic layer electrically connected to the third terminal; a second magnetic layer disposed between the first magnetic layer and the first portion; a first nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer; a third magnetic layer disposed between the first nonmagnetic layer and the second magnetic layer; and a second nonmagnetic layer disposed between the second magnetic layer and the third magnetic layer, a sign of a spin Hall angle of the second nonmagnetic layer being different from a sign of a spin Hall angle of the conductive layer.
    Type: Grant
    Filed: August 31, 2017
    Date of Patent: April 16, 2019
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Mizue Ishikawa, Yushi Kato, Yoshiaki Saito, Soichi Oikawa, Hiroaki Yoda
  • Publication number: 20190088860
    Abstract: A magnetic memory according to an embodiment includes: first to third terminals; a nonmagnetic conductive layer including first to third regions, the second region being disposed between the first and third regions, the first region being electrically connected to the first terminal, and the third region being electrically connected to the second terminal; and a magnetoresistive element disposed to correspond to the second region, including a first magnetic layer electrically connected to the third terminal, a second magnetic layer disposed between the first magnetic layer and the second region, and a nonmagnetic layer disposed between the first and second magnetic layers, the conductive layer including at least one of an alloy including Ir and Ta, an alloy including Ir and V, an alloy including Au and V, an alloy including Au and Nb, or an alloy including Pt and V, each of the alloys having an fcc structure.
    Type: Application
    Filed: March 6, 2018
    Publication date: March 21, 2019
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshiaki Saito, Tomoaki Inokuchi, Yushi Kato, Soichi Oikawa, Mizue Ishikawa, Hiroaki Yoda
  • Publication number: 20190080741
    Abstract: According to one embodiment, a magnetic memory device includes a conductive layer, a first magnetic layer, a second magnetic layer, a first nonmagnetic layer, and a controller. The conductive layer includes first and second portions, and a third portion between the first and second portions. The conductive layer includes a first metal and boron. The first magnetic layer is separated from the third portion in a first direction crossing a second direction. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The controller supplies a current to the conductive layer. The first metal includes at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
    Type: Application
    Filed: March 12, 2018
    Publication date: March 14, 2019
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yushi KATO, Yoshiaki SAITO, Mizue ISHIKAWA, Soichi OIKAWA, Hiroaki YODA
  • Publication number: 20190051818
    Abstract: According to one embodiment, a magnetic memory element includes a conductive layer, a first magnetic layer, a second magnetic layer, and a first nonmagnetic layer. The first magnetic layer is separated from the conductive layer. The second magnetic layer includes iron, platinum, and boron and is provided between the conductive layer and the first magnetic layer. The first nonmagnetic layer is provided between the first magnetic layer and the second magnetic layer. The conductive layer includes a first region and a second region. The second region includes a first metal and boron and is provided between the first region and the second magnetic layer. The first region does not include boron, or a first concentration of boron in the first region is lower than a second concentration of boron in the second region.
    Type: Application
    Filed: February 15, 2018
    Publication date: February 14, 2019
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Soichi OIKAWA, Yushi Kato, Mizue Ishikawa, Yoshiaki Saito, Hiroaki Yoda
  • Publication number: 20180366639
    Abstract: According to one embodiment, a magnetic memory device includes a conductive layer, first and second magnetic layers, a first nonmagnetic layer and a controller. The conductive layer includes first and second portions, and a third portion positioned between the first and second portions. The conductive layer includes a first metal. The first magnetic layer is separated from the third portion. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The second magnetic layer has first and second lattice lengths. The first lattice length is longer than the second lattice length. The controller implements a first operation of supplying a first current to the conductive layer, and a second operation of supplying a second current to the conductive layer.
    Type: Application
    Filed: February 26, 2018
    Publication date: December 20, 2018
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yushi Kato, Yoshiaki Saito, Soichi Oikawa, Mizue Ishikawa, Hiroaki Yoda
  • Publication number: 20180268886
    Abstract: A magnetic memory of an embodiment includes: first through third terminals; a conductive layer including first through third portions, the first portion being located between the second and third portions, the second and third portions being electrically connected to the first and second terminals respectively; and a magnetoresistive element including: a first magnetic layer electrically connected to the third terminal; a second magnetic layer disposed between the first magnetic layer and the first portion; a first nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer; a third magnetic layer disposed between the first nonmagnetic layer and the second magnetic layer; and a second nonmagnetic layer disposed between the second magnetic layer and the third magnetic layer, a sign of a spin Hall angle of the second nonmagnetic layer being different from a sign of a spin Hall angle of the conductive layer.
    Type: Application
    Filed: August 31, 2017
    Publication date: September 20, 2018
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Mizue ISHIKAWA, Yushi KATO, Yoshiaki SAITO, Soichi OIKAWA, Hiroaki YODA
  • Publication number: 20180174634
    Abstract: According to one embodiment, a magnetic memory device includes a conductive layer, a first magnetic layer, a second magnetic layer, a first nonmagnetic layer, and a controller. The conductive layer includes a first portion, a second portion, and a third portion between the first and second portions. The first magnetic layer is separated from the third portion. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The third portion includes a first region and a second region. The second region is provided between the first region and the second magnetic layer. The controller implements a first operation of supplying a first current to the conductive layer, and a second operation of supplying a second current to the conductive layer.
    Type: Application
    Filed: September 11, 2017
    Publication date: June 21, 2018
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yushi KATO, Soichi OIKAWA, Mizue ISHIKAWA, Yoshiaki SAITO, Hiroaki YODA
  • Publication number: 20180145247
    Abstract: A magnetic memory of an embodiment includes: a first terminal to third terminals; a first nonmagnetic layer, which is conductive, including a first portion, a second portion, and a third portion, the first portion being disposed between the second portion and the third portion, the second portion being electrically connected to the first terminal, and the third portion being electrically connected to the second terminal; a first magnetoresistive element including a first magnetic layer electrically connected to the third terminal, a second magnetic layer disposed between the first magnetic layer and the first portion, and a second nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer; and a first layer at least disposed between the first portion and the second magnetic layer, and including at least one of Mg, Al, Si, Hf, or a rare earth element, and at least one of oxygen or nitrogen.
    Type: Application
    Filed: January 19, 2018
    Publication date: May 24, 2018
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshiaki SAITO, Hiroaki Yoda, Yushi Kato, Mizue Ishikawa, Soichi Oikawa
  • Publication number: 20180040807
    Abstract: A magnetic memory of an embodiment includes: a first terminal to third terminals; a first nonmagnetic layer, which is conductive, including a first portion, a second portion, and a third portion, the first portion being disposed between the second portion and the third portion, the second portion being electrically connected to the first terminal, and the third portion being electrically connected to the second terminal; a first magnetoresistive element including a first magnetic layer electrically connected to the third terminal, a second magnetic layer disposed between the first magnetic layer and the first portion, and a second nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer; and a first layer at least disposed between the first portion and the second magnetic layer, and including at least one of Mg, Al, Si, Hf, or a rare earth element, and at least one of oxygen or nitrogen.
    Type: Application
    Filed: February 28, 2017
    Publication date: February 8, 2018
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshiaki SAITO, Hiroaki Yoda, Yushi Kato, Mizue Ishikawa, Soichi Oikawa
  • Publication number: 20170194026
    Abstract: According to one embodiment, a perpendicular magnetic recording medium includes a substrate, an underlayer including projections arranged at an average interval of 3 to 20 nm, an amorphous magnetic recording layer having a plurality of columnar magnetic grains on the surface of the projections, each having a magnetization easy axis in a direction perpendicular to a surface of the underlayer. The underlayer is formed such that 0.5d?r?1.5d, where r is the radius of curvature of a vertical section of each projection and d is the average interval between the projections.
    Type: Application
    Filed: March 4, 2016
    Publication date: July 6, 2017
    Applicants: Kabushiki Kaisha Toshiba, Kabushiki Kaisha Toshiba
    Inventors: Kaori Kimura, Soichi Oikawa, Takeshi Iwasaki
  • Patent number: 9633684
    Abstract: According to one embodiment, a magnetic recording medium includes a silicon oxide underlayer having a recess pattern having a plurality of recesses, a nonmagnetic underlayer having a first hole pattern having a plurality of holes corresponding to the recess pattern, and a magnetic recording layer having a second hole pattern having a plurality of holes connected with the first hole pattern. The silicon oxide underlayer, the nonmagnetic underlayer, and the magnetic recording layer are formed in order on the substrate.
    Type: Grant
    Filed: October 30, 2014
    Date of Patent: April 25, 2017
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akira Watanabe, Soichi Oikawa
  • Publication number: 20170004855
    Abstract: According to one embodiment, a perpendicular magnetic recording medium includes an underlying layer with convexes arranged with 1 to 20 nm intervals, and a multilayered amorphous magnetic recording layer formed on the underlying layer. The multilayered amorphous magnetic recording layer includes a first amorphous magnetic recording layer with a plurality of magnetic grains each formed on a corresponding convex to be widened toward its tip and being separated from each other at least in the convex side, a nonmagnetic protective layer covering at least a part of a sidewall of the magnetic particle, and a second amorphous magnetic recording layer formed on the nonmagnetic protective layer.
    Type: Application
    Filed: August 31, 2015
    Publication date: January 5, 2017
    Inventors: Kaori Kimura, Soichi Oikawa