Patents by Inventor Shoji Ikeda

Shoji Ikeda 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: 10586580
    Abstract: A magnetic tunnel junction element with a high tunnel magnetic resistance ratio can prevent a recording layer from being damaged. A reference layer includes a ferromagnetic body, and has magnetization direction fixed in the vertical direction. A barrier layer includes non-magnetic body, and disposed on one surface side of the reference layer. A recording layer is disposed to sandwich barrier layer between itself and reference layer. The recording layer includes a first ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in a vertical direction; a first non-magnetic layer including at least one of Mg, MgO, C, Li, Al, and Si, second non-magnetic layer including at least one of Ta, Hf, W, Mo, Nb, Zr, Y, Sc, Ti, V, and Cr, and second ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in a vertical direction.
    Type: Grant
    Filed: May 19, 2017
    Date of Patent: March 10, 2020
    Assignee: TOHOKU UNIVERSITY
    Inventors: Hiroaki Honjo, Shoji Ikeda, Hideo Sato, Tetsuo Endoh, Hideo Ohno
  • Publication number: 20200044142
    Abstract: The present invention provides a magnetoresistance effect element which has a high thermal stability factor ? and in which a magnetization direction of a recording layer is a perpendicular direction with respect to a film surface, and a magnetic memory including the same. Magnetic layers of a recording layer of the magnetoresistance effect element are divided into at least two, and an Fe composition with respect to a sum total of atomic fractions of magnetic elements in each magnetic layer is changed before stacking the magnetic layers.
    Type: Application
    Filed: January 18, 2017
    Publication date: February 6, 2020
    Inventors: Hiroaki HONJO, Tetsuo ENDOH, Shoji IKEDA, Hideo SATO, Hideo OHNO
  • Publication number: 20190363245
    Abstract: A structure used in the formation of a spintronics element, the spintronics element to include a plurality of laminated layers, includes a substrate, a plurality of laminated layers formed on the substrate, an uppermost layer of the plurality of laminated layers being a non-magnetic layer containing oxygen, and a protection layer directly formed on the uppermost layer, the protection layer preventing alteration of characteristics of the uppermost layer while exposed in an atmosphere including H2O, a partial pressure of H2O in the atmosphere being equal to or larger than 10?4 Pa, no other layer being directly formed on the protection layer.
    Type: Application
    Filed: July 16, 2019
    Publication date: November 28, 2019
    Applicant: TOHOKU UNIVERSITY
    Inventors: Soshi SATO, Masaaki NIWA, Hiroaki HONJO, Shoji IKEDA, Hideo OHNO, Tetsuo ENDO
  • Publication number: 20190304526
    Abstract: A magnetic tunnel junction element with a high MR ratio, and can prevent a recording layer from being damaged, and magnetic memory. A reference layer includes a ferromagnetic body, and has magnetization direction fixed in the vertical direction. A barrier layer includes non-magnetic body, and disposed on one surface side of the reference layer. A recording layer is disposed to sandwich barrier layer between itself and reference layer. The recording layer includes a first ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in vertical direction; a first non-magnetic layer including at least one of Mg, MgO, C, Li, Al, and Si, second non-magnetic layer including at least one of Ta, Hf, W, Mo, Nb, Zr, Y, Sc, Ti, V, and Cr, and second ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in vertical direction.
    Type: Application
    Filed: May 19, 2017
    Publication date: October 3, 2019
    Applicant: TOHOKU UNIVERSITY
    Inventors: Hiroaki HONJO, Shoji IKEDA, Hideo SATO, Tetsuo ENDOH, Hideo OHNO
  • Publication number: 20190304741
    Abstract: An evaluation method for an electronic device provided with an insulating film between a pair of electrode layers includes preparing a sample that has a tunnel barrier insulating film as the insulating film; irradiating the sample with electron beams from a plurality of angles to acquire a plurality of images; and performing image processing using the plurality of images to reconstruct a stereoscopic image and generate a cross-sectional image of the sample from the stereoscopic image.
    Type: Application
    Filed: March 21, 2019
    Publication date: October 3, 2019
    Inventors: Masaaki Niwa, Tetsuo Endoh, Shoji Ikeda, Kosuke Kimura
  • Patent number: 10424725
    Abstract: A spintronics element including a ferromagnetic layer containing boron, and a diffusion stopper film covering a side face of the ferromagnetic layer partially or entirely, the side face in direct contact with diffusion stopper film, so as to prevent out-diffusion of the boron contained in the ferromagnetic layer. The diffusion stopper film contains boron at a concentration higher than a concentration of the boron in a portion of the ferromagnetic layer where the ferromagnetic layer contacts the diffusion stopper film.
    Type: Grant
    Filed: June 20, 2018
    Date of Patent: September 24, 2019
    Assignee: TOHOKU UNIVERSITY
    Inventors: Soshi Sato, Masaaki Niwa, Hiroaki Honjo, Shoji Ikeda, Hideo Sato, Hideo Ohno, Tetsuo Endoh
  • Patent number: 10396274
    Abstract: A method of manufacturing a spintronics element from laminated layers. The method includes (a) forming a plurality of laminated layers in manufacturing equipment, (b) forming a wafer in the manufacturing equipment, including applying a protection layer directly on a non-magnetic uppermost layer of the laminated layers so that the protection layer prevents alteration of characteristics of the uppermost layer, and (c) exposing the wafer, outside of the manufacturing equipment, to an atmosphere that includes H2O having a partial pressure in the atmosphere equal to or larger than 10?4 Pa.
    Type: Grant
    Filed: March 8, 2016
    Date of Patent: August 27, 2019
    Assignee: TOHOKU UNIVERSITY
    Inventors: Soshi Sato, Masaaki Niwa, Hiroaki Honjo, Shoji Ikeda, Hideo Ohno, Tetsuo Endo
  • Publication number: 20190229262
    Abstract: A magnetic tunnel junction element configured by stacking, in a following stack order, a fixed layer formed of a ferromagnetic body and in which a magnetization direction is fixed, a magnetic coupling layer formed of a nonmagnetic body, a reference layer formed of a ferromagnetic body and in which the magnetization direction is fixed, a barrier layer formed of a nonmagnetic body, and a recording layer formed of a ferromagnetic body, a barrier layer formed of a nonmagnetic body, and a recording layer formed by sandwiching an insertion layer formed of a nonmagnetic body between first and second ferromagnetic layers, wherein the magnetic coupling layer is formed using a sputtering gas in which a value of a ratio in which a mass number of an element used in the magnetic coupling layer divided by the mass number of the sputtering gas itself is 2.2 or smaller.
    Type: Application
    Filed: March 17, 2017
    Publication date: July 25, 2019
    Applicant: TOHOKU UNIVERSITY
    Inventors: Hiroaki Honjo, Shoji Ikeda, Hideo Sato, Tetsuo Endoh, Hideo Ohno
  • Publication number: 20190198755
    Abstract: A method for producing a magnetic memory includes: forming a magnetic film having a non-magnetic layer between a first magnetic layer and a second magnetic layer on a substrate having an electrode layer; performing annealing treatment at a first treatment temperature in a state where a magnetic field is applied in a direction perpendicular to a film surface of the first or the second magnetic layer in vacuum; forming a magnetic tunnel junction element; forming a protective film protecting the magnetic tunnel junction element; a formation accompanied by thermal history, in which a constituent element of a magnetic memory is formed after the protective film formation on the substrate; and implementing annealing treatment at a second treatment temperature lower than the first treatment temperature on the substrate in an annealing treatment chamber, in vacuum or inert gas wherein no magnetic field is applied.
    Type: Application
    Filed: August 28, 2017
    Publication date: June 27, 2019
    Inventors: Kenchi ITO, Tetsuo ENDOH, Shoji IKEDA, Hideo SATO, Hideo OHNO, Sadahiko MIURA, Masaaki NIWA, Hiroaki HONJO
  • Publication number: 20190189917
    Abstract: A magnetic tunnel junction element includes, in a following stack order, an underlayer formed of a metal material, a fixed layer formed of a ferromagnetic body, a magnetic coupling layer formed of a nonmagnetic body, a reference layer formed of a ferromagnetic body, a barrier layer formed of a nonmagnetic body, and a recording layer formed of a ferromagnetic body, or alternatively, the magnetic tunnel junction element includes, in a following stack order, a recording layer formed of a ferromagnetic body, a barrier layer formed of a nonmagnetic body, a reference layer formed of a ferromagnetic body, a magnetic coupling layer formed of a nonmagnetic body, an underlayer formed of a metal material, and a fixed layer formed of a ferromagnetic body, wherein the fixed layer is formed and stacked after performing plasma treatment to a surface of the underlayer having been formed.
    Type: Application
    Filed: March 21, 2017
    Publication date: June 20, 2019
    Applicant: TOHOKU UNIVERSITY
    Inventors: Hiroaki Honjo, Tetsuo Endoh, Shoji Ikeda, Hideo Sato, Hideo Ohno
  • Patent number: 10263180
    Abstract: A magnetoresistance effect element includes a reference layer made of a ferromagnetic material, a recording layer made of a ferromagnetic material, and a barrier layer disposed between the reference layer and the recording layer. The reference layer and the recording layer have an in-plane magnetization direction parallel to a surface of the layers. The recording layer has a shape that has short axis and long axis perpendicular to the short axis in plan view. A first value obtained by dividing a thickness of the recording layer by a length of the short axis of the recording layer is greater than 0.3 and smaller than 1.
    Type: Grant
    Filed: July 22, 2017
    Date of Patent: April 16, 2019
    Assignee: TOHOKU UNIVERSITY
    Inventors: Hideo Sato, Shinya Ishikawa, Shunsuke Fukami, Shoji Ikeda, Fumihiro Matsukura, Hideo Ohno, Tetsuo Endoh
  • Publication number: 20190074433
    Abstract: A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface of the layers. An atomic fraction of all magnetic elements to all magnetic and non-magnetic elements included in the second magnetic layer is smaller than that of the first magnetic layer.
    Type: Application
    Filed: November 2, 2018
    Publication date: March 7, 2019
    Applicant: TOHOKU UNIVERSITY
    Inventors: Hideo SATO, Shoji IKEDA, Mathias BERSWEILER, Hiroaki HONJO, Kyota WATANABE, Shunsuke FUKAMI, Fumihiro MATSUKURA, Kenchi ITO, Masaaki NIWA, Tetsuo ENDOH, Hideo OHNO
  • Publication number: 20190019944
    Abstract: A magnetic tunnel junction element (10) includes a configuration in which a reference layer (14) that includes a ferromagnetic material, a barrier layer (15) that includes O, a recording layer (16) that includes a ferromagnetic material including Co or Fe, a first protective layer (17) that includes O, and a second protective layer (18) that includes at least one of Pt, Ru, Co, Fe, CoB, FeB, or CoFeB are layered.
    Type: Application
    Filed: November 18, 2016
    Publication date: January 17, 2019
    Inventors: Hideo Sato, Yoshihisa Horikawa, Shunsuke Fukami, Shoji Ikeda, Fumihiro Matsukura, Hideo Ohno, Tetsuo Endoh, Hiroaki Honjo
  • Patent number: 10164174
    Abstract: A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface if the layers. The second magnetic layer has a saturation magnetization lower than that of the first magnetic layer, and an interfacial magnetic anisotropy energy density (Ki) at the interface between the first magnetic layer and the first non-magnetic layer is greater than that of an interface between the first non-magnetic layer and second magnetic layers if being disposed adjacent each other.
    Type: Grant
    Filed: January 16, 2018
    Date of Patent: December 25, 2018
    Assignee: TOHOKU UNIVERSITY
    Inventors: Hideo Sato, Shoji Ikeda, Mathias Bersweiler, Hiroaki Honjo, Kyota Watanabe, Shunsuke Fukami, Fumihiro Matsukura, Kenchi Ito, Masaaki Niwa, Tetsuo Endoh, Hideo Ohno
  • Patent number: 10127957
    Abstract: A control method for a magnetoresistance effect element and a control device for the magnetoresistance effect element that provide a higher writing speed and lower power consumption. When the magnetization direction of a second magnetic layer is nearly parallel to the magnetization direction of a first magnetic layer, a first voltage is applied across the first and second magnetic layer so that the magnetization direction of the second magnetic layer is reversed by modifying the direction of the magnetization easy axis thereof, followed by the application of a second voltage. When the magnetization direction of the second magnetic layer is nearly antiparallel to the magnetization direction of the first magnetic layer, a third voltage is applied across the first magnetic layer and the second magnetic layer, followed by the application of a fourth voltage so that current flows from the second magnetic layer toward the first magnetic layer.
    Type: Grant
    Filed: November 13, 2014
    Date of Patent: November 13, 2018
    Assignee: TOHOKU UNIVERSITY
    Inventors: Shun Kanai, Fumihiro Matsukura, Hideo Ohno, Michihiko Yamanouchi, Shoji Ikeda, Hideo Sato
  • Publication number: 20180301621
    Abstract: A spintronics element including a ferromagnetic layer containing boron, and a diffusion stopper film covering a side face of the ferromagnetic layer partially or entirely, the side face in direct contact with diffusion stopper film, so as to prevent out-diffusion of the boron contained in the ferromagnetic layer. The diffusion stopper film contains boron at a concentration higher than a concentration of the boron in a portion of the ferromagnetic layer where the ferromagnetic layer contacts the diffusion stopper film.
    Type: Application
    Filed: June 20, 2018
    Publication date: October 18, 2018
    Applicant: TOHOKU UNIVERSITY
    Inventors: Soshi SATO, Masaaki NIWA, Hiroaki HONJO, Shoji IKEDA, Hideo SATO, Hideo OHNO, Tetsuo ENDOH
  • Publication number: 20180175286
    Abstract: A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface if the layers. The second magnetic layer has a saturation magnetization lower than that of the first magnetic layer, and an interfacial magnetic anisotropy energy density (Ki) at the interface between the first magnetic layer and the first non-magnetic layer is greater than that of an interface between the first non-magnetic layer and second magnetic layers if being disposed adjacent each other.
    Type: Application
    Filed: January 16, 2018
    Publication date: June 21, 2018
    Applicant: TOHOKU UNIVERSITY
    Inventors: Hideo SATO, Shoji IKEDA, Mathias BERSWEILER, Hiroaki HONJO, Kyota WATANABE, Shunsuke FUKAMI, Fumihiro MATSUKURA, Kenchi ITO, Masaaki NIWA, Tetsuo ENDOH, Hideo OHNO
  • Publication number: 20170324030
    Abstract: A magnetoresistance effect element includes a reference layer made of a ferromagnetic material, a recording layer made of a ferromagnetic material, and a barrier layer disposed between the reference layer and the recording layer. The reference layer and the recording layer have an in-plane magnetization direction parallel to a surface of the layers. The recording layer has a shape that has short axis and long axis perpendicular to the short axis in plan view. A first value obtained by dividing a thickness of the recording layer by a length of the short axis of the recording layer is greater than 0.3 and smaller than 1.
    Type: Application
    Filed: July 22, 2017
    Publication date: November 9, 2017
    Applicant: TOHOKU UNIVERSITY
    Inventors: Hideo SATO, Shinya ISHIKAWA, Shunsuke FUKAMI, Shoji IKEDA, Fumihiro MATSUKURA, Hideo OHNO, Tetsuo ENDOH
  • Patent number: 9799822
    Abstract: A disclosed magnetic memory element includes: a magnetization free layer formed of a ferromagnetic substance having perpendicular magnetic anisotropy; a response layer provided so as to be opposed to the magnetization free layer and formed of a ferromagnetic substance having perpendicular magnetic anisotropy; a non-magnetic layer provided so as to be opposed to the response layer on a side opposite to the magnetization free layer and formed of a non-magnetic substance; and a reference layer provided so as to be opposed to the non-magnetic layer on a side opposite to the response layer and formed of a ferromagnetic substance having perpendicular magnetic anisotropy. The magnetization free layer includes a first magnetization fixed region and a second magnetization fixed region which have magnetization fixed in directions antiparallel to each other, and a magnetization free region in which a magnetization direction is variable.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: October 24, 2017
    Assignees: NEC CORPORATION, TOHOKU UNIVERSITY
    Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi
  • Publication number: 20170263854
    Abstract: A method of manufacturing a spintronics element from laminated layers. The method includes (a) forming a plurality of laminated layers in manufacturing equipment, (b) forming a wafer in the manufacturing equipment, including applying a protection layer directly on a non-magnetic uppermost layer of the laminated layers so that the protection layer prevents alteration of characteristics of the uppermost layer, and (c) exposing the wafer, outside of the manufacturing equipment, to an atmosphere that includes H2O having a partial pressure in the atmosphere equal to or larger than 10?4 Pa.
    Type: Application
    Filed: March 8, 2016
    Publication date: September 14, 2017
    Applicant: TOHOKU UNIVERSITY
    Inventors: Soshi SATO, Masaaki NIWA, Hiroaki HONJO, Shoji IKEDA, Hideo OHNO, Tetsuo ENDO