Patents by Inventor Katsuyuki Nakada

Katsuyuki Nakada 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).

  • Publication number: 20200212295
    Abstract: A magnetoresistive effect element includes a first ferromagnetic layer and a tunnel barrier layer. The tunnel barrier layer has a main body region and a first interface region. The main body region has an oxide material of a first spinel structure represented by a general formula LM2O4. The first interface region has at least one element X selected from a group consisting of elements having a valence of 2 and elements having a valence of 3 excluding Al and has an oxide material of a second spinel structure represented by a general formula DG2O4(D represents one or more kinds of elements including Mg or the element X, and G represents one or more kinds of elements including Al or the element X). A content of the element X contained in the first interface region is larger than that of the element X contained in the main body region.
    Type: Application
    Filed: March 26, 2019
    Publication date: July 2, 2020
    Applicant: TDK CORPORATION
    Inventors: Tsuyoshi SUZUKI, Katsuyuki NAKADA, Shinto ICHIKAWA
  • Patent number: 10685671
    Abstract: A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, and the tunnel barrier layer has a spinel structure represented by a composition formula AGa2Ox (0<x?4), and an A-site is a non-magnetic divalent cation which is one or more selected from a group consisting of magnesium, zinc and cadmium.
    Type: Grant
    Filed: February 15, 2019
    Date of Patent: June 16, 2020
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Katsuyuki Nakada, Tatsuo Shibata
  • Patent number: 10665776
    Abstract: Provided is a magnetoresistance effect element in which a tunnel barrier layer stably has a cation disordered spinel structure. This magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a tunnel barrier layer disposed between the first ferromagnetic layer and the second ferromagnetic layer. In addition, the tunnel barrier layer is an oxide of MgxAl1-x (0?x<1) and an amount of oxygen in the tunnel barrier layer is lower than an amount of oxygen in a fully oxidized state in which the oxide has an ordered spinel structure.
    Type: Grant
    Filed: February 14, 2019
    Date of Patent: May 26, 2020
    Assignees: TDK CORPORATION, NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventors: Shinto Ichikawa, Katsuyuki Nakada, Seiji Mitani, Hiroaki Sukegawa, Kazuhiro Hono, Tadakatsu Ohkubo
  • Patent number: 10665374
    Abstract: There is provided a magnetoresistive effect element having improved magnetoresistive effect. A magnetoresistive effect element MR includes a first ferromagnetic layer 4 as a fixed magnetization layer, a second ferromagnetic layer 6 as a free magnetization layer, and a nonmagnetic spacer layer 5 provided between the first ferromagnetic layer 4 and the second ferromagnetic layer 6. The nonmagnetic spacer layer 5 includes at least one of a first insertion layer 5A provided under the nonmagnetic spacer layer 5 and a second insertion layer 5C provided over the nonmagnetic spacer layer 5. The first insertion layer 5A and the second insertion layer 5C are made of Fe2TiSi.
    Type: Grant
    Filed: September 9, 2019
    Date of Patent: May 26, 2020
    Assignee: TDK CORPORATION
    Inventors: Kazuumi Inubushi, Katsuyuki Nakada, Tomoyuki Sasaki
  • Publication number: 20200127193
    Abstract: A magnetoresistive effect element, which includes: a first ferromagnetic layer as a magnetization fixed layer; a second ferromagnetic layer as a magnetization free layer; and a nonmagnetic spacer layer provided between the first ferromagnetic layer and the second ferromagnetic layer. The nonmagnetic spacer layer includes an Ag alloy represented by General Formula (1), and thereby lattice mismatch between the nonmagnetic spacer layer, and the first ferromagnetic layer and/or the second ferromagnetic layer is reduced, compared to lattice mismatch when the nonmagnetic spacer layer is formed of Ag, Ag? X1-???(1) where X indicates one element selected from the group made of Al, Cu, Ga, Ge, As, Y, La, Sm, Yb, and Pt, and 0<?<1.
    Type: Application
    Filed: December 19, 2019
    Publication date: April 23, 2020
    Applicant: TDK CORPORATION
    Inventors: Kazuumi INUBUSHI, Katsuyuki NAKADA
  • Patent number: 10629796
    Abstract: A laminate includes, on a substrate, a first buffer layer substantially made of zirconium oxide or stabilized zirconia, a second buffer layer substantially made of yttrium oxide, a metal layer substantially made of at least one among platinum, iridium, palladium, rhodium, vanadium, chromium, iron, molybdenum, tungsten, aluminum, silver, gold, copper, and nickel, and a magnesium oxide layer substantially made of magnesium oxide, in this order.
    Type: Grant
    Filed: March 19, 2018
    Date of Patent: April 21, 2020
    Assignee: TDK CORPORATION
    Inventors: Kazuya Maekawa, Makoto Shibata, Katsuyuki Nakada, Yohei Shiokawa, Kazuumi Inubushi
  • Patent number: 10629801
    Abstract: A laminated structure includes a ferromagnetic layer, a multiferroic layer provided on one surface of the ferromagnetic layer, and a ferroelectric layer which is provided on the multiferroic layer opposite to the ferromagnetic layer and has a permittivity greater than that of the multiferroic layer.
    Type: Grant
    Filed: April 2, 2018
    Date of Patent: April 21, 2020
    Assignee: TDK CORPORATION
    Inventors: Eiji Suzuki, Katsuyuki Nakada, Shogo Yonemura
  • Publication number: 20200075845
    Abstract: A magnetoresistive effect element includes a first ferromagnetic layer, a second ferromagnetic layer, a nonmagnetic layer, and at least one of a first nonmagnetic insertion layer provided directly on a lower surface of the nonmagnetic layer and a second nonmagnetic insertion layer provided directly on an upper surface of the nonmagnetic layer. The first nonmagnetic insertion layer and the second nonmagnetic insertion layer include an Ag alloy represented by General Formula (1): Ag?X1-? where X indicates one element selected from the group consisting of Al, Cu, Ga, Ge, As, Y, La, Sm, Yb, and Pt, and 0<?<1.
    Type: Application
    Filed: November 7, 2019
    Publication date: March 5, 2020
    Applicant: TDK CORPORATION
    Inventors: Kazuumi INUBUSHI, Katsuyuki NAKADA
  • Publication number: 20200052194
    Abstract: A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, and the tunnel barrier layer has a spinel structure in which cations are disordered, and contains a divalent cation of a non-magnetic element, a trivalent cation of a non-magnetic element, oxygen, and one of nitrogen and fluorine.
    Type: Application
    Filed: September 30, 2019
    Publication date: February 13, 2020
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Tatsuo SHIBATA, Katsuyuki NAKADA, Yoshitomo TANAKA
  • Patent number: 10559749
    Abstract: A magnetoresistive effect element, which includes: a first ferromagnetic layer as a magnetization fixed layer; a second ferromagnetic layer as a magnetization free layer; and a nonmagnetic spacer layer provided between the first ferromagnetic layer and the second ferromagnetic layer. The nonmagnetic spacer layer includes an Ag alloy represented by General Formula (1), and thereby lattice mismatch between the nonmagnetic spacer layer, and the first ferromagnetic layer and/or the second ferromagnetic layer is reduced, compared to lattice mismatch when the nonmagnetic spacer layer is formed of Ag, Ag?X1-???(1) where X indicates one element selected from the group made of Al, Cu, Ga, Ge, As, Y, La, Sm, Yb, and Pt, and 0<?<1.
    Type: Grant
    Filed: January 17, 2018
    Date of Patent: February 11, 2020
    Assignee: TDK CORPORATION
    Inventors: Kazuumi Inubushi, Katsuyuki Nakada
  • Publication number: 20200035913
    Abstract: A magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a tunnel barrier layer that is interposed between the first ferromagnetic layer and the second ferromagnetic layer. The tunnel barrier layer is a stacked body including one or more high-barrier-height layers and one or more low-barrier-height layers, the one or more high-barrier-height layers having a relatively high barrier height with respect to the one or more low-barrier-height layers and the one or more low-barrier-height layers having a relatively low barrier height with respect to the one or more high-barrier-height layers. A minimum difference of barrier height between the one or more high-barrier-height layers and the one or more low-barrier-height layers is equal to or higher than 0.5 eV.
    Type: Application
    Filed: July 8, 2019
    Publication date: January 30, 2020
    Applicant: TDK CORPORATION
    Inventors: Shinto ICHIKAWA, Katsuyuki NAKADA, Tomoyuki SASAKI
  • Publication number: 20200027476
    Abstract: A nonmagnetic spacer layer in a magnetoresistive effect element includes a nonmagnetic metal layer that is formed of Ag and at least one of a first insertion layer that is disposed on a bottom surface of the nonmagnetic metal layer and a second insertion layer that is disposed on a top surface of the nonmagnetic metal layer. The first insertion layer and the second insertion layer include an Fe alloy that is expressed by Fe?X1-?. Here, X denotes one or more elements selected from a group consisting of O, Al, Si, Ga, Mo, Ag, and Au, and ? satisfies 0<?<1.
    Type: Application
    Filed: September 10, 2019
    Publication date: January 23, 2020
    Applicant: TDK CORPORATION
    Inventors: Kazuumi INUBUSHI, Katsuyuki NAKADA
  • Publication number: 20200006642
    Abstract: A magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a tunnel barrier layer that is interposed between the first ferromagnetic layer and the second ferromagnetic layer. The tunnel barrier layer is a stacked body including one or more first oxide layers having a spinel structure and one or more second oxide layers having a spinel structure with a composition which is different from a composition of the first oxide layer.
    Type: Application
    Filed: June 25, 2019
    Publication date: January 2, 2020
    Applicant: TDK CORPORATION
    Inventors: Shinto ICHIKAWA, Katsuyuki NAKADA, Tomoyuki SASAKI
  • Publication number: 20190392972
    Abstract: There is provided a magnetoresistive effect element having improved magnetoresistive effect. A magnetoresistive effect element MR includes a first ferromagnetic layer 4 as a fixed magnetization layer, a second ferromagnetic layer 6 as a free magnetization layer, and a nonmagnetic spacer layer 5 provided between the first ferromagnetic layer 4 and the second ferromagnetic layer 6. The nonmagnetic spacer layer 5 includes at least one of a first insertion layer 5A provided under the nonmagnetic spacer layer 5 and a second insertion layer 5C provided over the nonmagnetic spacer layer 5. The first insertion layer 5A and the second insertion layer 5C are made of Fe2TiSi.
    Type: Application
    Filed: September 9, 2019
    Publication date: December 26, 2019
    Applicant: TDK CORPORATION
    Inventors: Kazuumi INUBUSHI, Katsuyuki NAKADA, Tomoyuki SASAKI
  • Publication number: 20190378974
    Abstract: A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, and the tunnel barrier layer has a spinel structure represented by a composition formula of AIn2Ox(0<x?4), and an A-site is a non-magnetic divalent cation which is one or more selected from a group consisting of magnesium, zinc and cadmium.
    Type: Application
    Filed: August 16, 2019
    Publication date: December 12, 2019
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Katsuyuki NAKADA, Tatsuo SHIBATA
  • Patent number: 10505105
    Abstract: A magnetoresistive effect element includes: a first ferromagnetic layer as a magnetization fixed layer; a second ferromagnetic layer as a magnetization free layer; and a nonmagnetic spacer layer provided between the first ferromagnetic layer and the second ferromagnetic layer. The nonmagnetic spacer layer includes a nonmagnetic metal layer formed of Ag, and at least one of a first nonmagnetic insertion layer provided on a lower surface of the nonmagnetic metal layer and a second nonmagnetic insertion layer provided on an upper surface of the nonmagnetic metal layer. The first nonmagnetic insertion layer and the second nonmagnetic insertion layer include an Ag alloy, and thereby lattice mismatch between the nonmagnetic spacer layer, and the first ferromagnetic layer and/or the second ferromagnetic layer is reduced, compared to lattice mismatch when the entire nonmagnetic spacer layer is formed of Ag.
    Type: Grant
    Filed: January 18, 2018
    Date of Patent: December 10, 2019
    Assignee: TDK CORPORATION
    Inventors: Kazuumi Inubushi, Katsuyuki Nakada
  • Publication number: 20190355898
    Abstract: A magnetoresistance effect element includes: a first ferromagnetic layer; a second ferromagnetic layer; and a tunnel barrier layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer, wherein the tunnel barrier layer is an oxide having a spinel structure, and the tunnel barrier layer includes a magnetic element as an additional element.
    Type: Application
    Filed: May 15, 2019
    Publication date: November 21, 2019
    Applicant: TDK CORPORATION
    Inventor: Katsuyuki NAKADA
  • Patent number: 10468589
    Abstract: A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, and the tunnel barrier layer has a spinel structure in which cations are disordered, and contains a divalent cation of a non-magnetic element, a trivalent cation of a non-magnetic element, oxygen, and one of nitrogen and fluorine.
    Type: Grant
    Filed: September 26, 2018
    Date of Patent: November 5, 2019
    Assignee: TDK CORPORATION
    Inventors: Tomoyuki Sasaki, Tatsuo Shibata, Katsuyuki Nakada, Yoshitomo Tanaka
  • Patent number: 10461244
    Abstract: A laminated structure according to an embodiment includes: a ferromagnetic layer; and a multiferroic layer formed on one surface of the ferromagnetic layer, wherein a surface of the multiferroic layer on the ferromagnetic layer side includes a first region, a crystalline phase of which is rhombohedral, and a second region, a crystalline phase of which is tetragonal.
    Type: Grant
    Filed: May 31, 2018
    Date of Patent: October 29, 2019
    Assignee: TDK CORPORATION
    Inventors: Eiji Suzuki, Katsuyuki Nakada
  • Publication number: 20190325903
    Abstract: A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, and the tunnel barrier layer has a spinel structure represented by a composition formula AGa2Ox (0<x?4), and an A-site is a non-magnetic divalent cation which is one or more selected from a group consisting of magnesium, zinc and cadmium.
    Type: Application
    Filed: February 15, 2019
    Publication date: October 24, 2019
    Applicant: TDK CORPORATION
    Inventors: Tomoyuki SASAKI, Katsuyuki NAKADA, Tatsuo SHIBATA