Patents by Inventor Yoshiaki Sonobe

Yoshiaki Sonobe 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: 10879451
    Abstract: Disclosed is a magnetic tunnel junction device whose fixed layer has a simplified structure and in which the number of stacked layers is reduced. The magnetic tunnel junction device comprises a free layer whose magnetization direction is variable, a fixed layer whose magnetization direction is fixed and that is formed as a single layer, and a dielectric layer stacked between the free layer and the fixed layer. One or more of the free layer and the fixed layer are an L11 type magnetic alloy layer, and the dielectric layer has a (111) texture.
    Type: Grant
    Filed: August 9, 2019
    Date of Patent: December 29, 2020
    Inventors: Hiroyoshi Itoh, Yoshiaki Sonobe
  • Patent number: 10840435
    Abstract: Provided are a magnetic tunnel junction device and a magnetic resistance memory device which are capable of both reducing a write current and increasing a write speed. The magnetic tunnel junction device includes a free layer having a first magnetization direction that is changeable, a pinned layer that is configured to maintain a second magnetization direction in a predetermined direction, and an insulating layer between the free layer and the pinned layer. The free layer includes a first free layer having perpendicular magnetic anisotropy and high polarizability, and a second free layer that is antiferromagnetic-coupled to the first free layer.
    Type: Grant
    Filed: July 31, 2019
    Date of Patent: November 17, 2020
    Assignee: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Yoshiaki Sonobe, Yoshinobu Nakatani
  • Publication number: 20200212104
    Abstract: A magnetic tunnel junction (MTJ) element includes a free layer, a pinned layer on the free layer, and a dielectric layer extending between the free layer and the pinned layer. A spin orbit torque (SOT) generator is provided, which contacts at least a portion of the free layer. A plane extending between the SOT generator and the free layer intersects a plane extending between the free layer and the dielectric layer. The SOT generator is configured to modulate current that passes between the free layer, the dielectric layer, and the pinned layer. This SOT generator can include a pair of electrodes that are spaced apart from each other in a direction orthogonal to a stacking direction of the free layer, the dielectric layer and the pinned layer. This SOT generator may include a metal selected from a group consisting of Pt, W, and Ta, or may include a topological insulator.
    Type: Application
    Filed: December 27, 2019
    Publication date: July 2, 2020
    Inventor: Yoshiaki SONOBE
  • Patent number: 10679686
    Abstract: A magnetoresistive memory device includes a memory cell including a magnetic tunnel junction element, a detector to detect a current value writable in units of the memory cell, a current value storage area, and a current controller. The current value storage area stores at least one of a maximum value and a minimum value of the writable current value detected by the detector. The current controller performs at least one control operation of an operation of controlling a write current value of the memory cell based on the maximum value and an operation of controlling a read current value of the memory cell based on the minimum value.
    Type: Grant
    Filed: August 2, 2019
    Date of Patent: June 9, 2020
    Assignee: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Masatoshi Sonoda, Yoshiaki Sonobe, Takeshi Kato
  • Publication number: 20200144482
    Abstract: Provided are a magnetic tunnel junction device and a magnetic resistance memory device which are capable of both reducing a write current and increasing a write speed. The magnetic tunnel junction device includes a free layer having a first magnetization direction that is changeable, a pinned layer that is configured to maintain a second magnetization direction in a predetermined direction, and an insulating layer between the free layer and the pinned layer. The free layer includes a first free layer having perpendicular magnetic anisotropy and high polarizability, and a second free layer that is antiferromagnetic-coupled to the first free layer.
    Type: Application
    Filed: July 31, 2019
    Publication date: May 7, 2020
    Inventors: Yoshiaki Sonobe, Yoshinobu Nakatani
  • Publication number: 20200058846
    Abstract: Disclosed is a magnetic tunnel junction device whose fixed layer has a simplified structure and in which the number of stacked layers is reduced. The magnetic tunnel junction device comprises a free layer whose magnetization direction is variable, a fixed layer whose magnetization direction is fixed and that is formed as a single layer, and a dielectric layer stacked between the free layer and the fixed layer. One or more of the free layer and the fixed layer are an L11 type magnetic alloy layer, and the dielectric layer has a (111) texture.
    Type: Application
    Filed: August 9, 2019
    Publication date: February 20, 2020
    Inventors: Hiroyoshi Itoh, Yoshiaki Sonobe
  • Patent number: 10566042
    Abstract: Magnetic tunnel junction devices are provided. A magnetic tunnel junction device includes a pinned layer. The magnetic tunnel junction device includes a free layer on the pinned layer. The free layer includes a first layer, a second layer that is on the first layer, and a third layer that is between the first layer and the second layer. A Curie temperature of the third layer is lower than a Curie temperature of the first layer and lower than a Curie temperature of the second layer. Moreover, the magnetic tunnel junction device includes an insulating layer that is between the pinned layer and the free layer. Related magnetoresistive memory devices are also provided.
    Type: Grant
    Filed: October 24, 2018
    Date of Patent: February 18, 2020
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ken Machida, Yoshiaki Sonobe, Takeshi Kato
  • Publication number: 20190355403
    Abstract: A magnetoresistive memory device includes a memory cell including a magnetic tunnel junction element, a detector to detect a current value writable in units of the memory cell, a current value storage area, and a current controller. The current value storage area stores at least one of a maximum value and a minimum value of the writable current value detected by the detector. The current controller performs at least one control operation of an operation of controlling a write current value of the memory cell based on the maximum value and an operation of controlling a read current value of the memory cell based on the minimum value.
    Type: Application
    Filed: August 2, 2019
    Publication date: November 21, 2019
    Inventors: Masatoshi SONODA, Yoshiaki SONOBE, Takeshi KATO
  • Patent number: 10431279
    Abstract: A magnetoresistive memory device includes a memory cell including a magnetic tunnel junction element, a detector to detect a current value writable in units of the memory cell, a current value storage area, and a current controller. The current value storage area stores at least one of a maximum value and a minimum value of the writable current value detected by the detector. The current controller performs at least one control operation of an operation of controlling a write current value of the memory cell based on the maximum value and an operation of controlling a read current value of the memory cell based on the minimum value.
    Type: Grant
    Filed: December 14, 2017
    Date of Patent: October 1, 2019
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Masatoshi Sonoda, Yoshiaki Sonobe, Takeshi Kato
  • Patent number: 10395809
    Abstract: Embodiments of the inventive concepts provide a flat perpendicular magnetic layer having a low saturation magnetization and a perpendicular magnetization-type tunnel magnetoresistive element using the same. The perpendicular magnetic layer is a nitrogen-poor (Mn1?xGax)Ny layer (0<x?0.5 and 0<y<0.1) formed by providing nitrogen (N) into a MnGa alloy while adjusting a nitrogen amount. The perpendicular magnetic layer can be formed flat.
    Type: Grant
    Filed: May 10, 2017
    Date of Patent: August 27, 2019
    Assignees: Samsung Electronics Co., Ltd., National Institute for Materials Science
    Inventors: Shigeki Takahashi, Yoshiaki Sonobe, Hiroaki Sukegawa, Hwachol Lee, Kazuhiro Hono, Seiji Mitani, Jun Liu
  • Publication number: 20190164587
    Abstract: Magnetic tunnel junction devices are provided. A magnetic tunnel junction device includes a pinned layer. The magnetic tunnel junction device includes a free layer on the pinned layer. The free layer includes a first layer, a second layer that is on the first layer, and a third layer that is between the first layer and the second layer. A Curie temperature of the third layer is lower than a Curie temperature of the first layer and lower than a Curie temperature of the second layer. Moreover, the magnetic tunnel junction device includes an insulating layer that is between the pinned layer and the free layer. Related magnetoresistive memory devices are also provided.
    Type: Application
    Filed: October 24, 2018
    Publication date: May 30, 2019
    Inventors: KEN MACHIDA, YOSHIAKI SONOBE, TAKESHI KATO
  • Patent number: 10170695
    Abstract: A magnetic tunnel junction device includes a Heusler alloy layer that has not only a perpendicular magnetic anisotropy characteristic, but also a half-metallicity characteristic. For example, the magnetic tunnel junction device includes at least one Heusler alloy layer and a barrier layer. The barrier layer is in contact with the Heusler alloy layer and has an insulating property. A compressive strain is exerted on the Heusler alloy layer in a direction parallel to an interface between the Heusler alloy layer and the barrier layer.
    Type: Grant
    Filed: September 30, 2016
    Date of Patent: January 1, 2019
    Assignee: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Yoshiaki Sonobe, Hiroyoshi Itoh
  • Publication number: 20180226115
    Abstract: A magnetoresistive memory device includes a memory cell including a magnetic tunnel junction element, a detector to detect a current value writable in units of the memory cell, a current value storage area, and a current controller. The current value storage area stores at least one of a maximum value and a minimum value of the writable current value detected by the detector. The current controller performs at least one control operation of an operation of controlling a write current value of the memory cell based on the maximum value and an operation of controlling a read current value of the memory cell based on the minimum value.
    Type: Application
    Filed: December 14, 2017
    Publication date: August 9, 2018
    Inventors: Masatoshi SONODA, Yoshiaki SONOBE, Takeshi KATO
  • Publication number: 20180069173
    Abstract: A free layer has a switchable magnetization direction. A reference layer has a fixed magnetization direction. A barrier layer is provided between the free layer and the reference layer. The free layer includes a perpendicularity-maintaining layer and a high-polarizability magnetic layer. The perpendicularity-maintaining layer, if in contact with the barrier layer, has a first surface roughness. The high-polarizability magnetic layer, if in contact with the barrier layer, has a second surface roughness. If the first surface roughness is smaller than the second surface roughness, the perpendicularity-maintaining layer is in contact with the barrier layer. If the second surface roughness is smaller than the first surface roughness, the high-polarizability magnetic layer is in contact with the barrier layer.
    Type: Application
    Filed: August 18, 2017
    Publication date: March 8, 2018
    Inventors: Yoshiaki SONOBE, Shigeki NAKAGAWA
  • Publication number: 20170330668
    Abstract: Embodiments of the inventive concepts provide a flat perpendicular magnetic layer having a low saturation magnetization and a perpendicular magnetization-type tunnel magnetoresistive element using the same. The perpendicular magnetic layer is a nitrogen-poor (Mn1?xGax)Ny layer (0<x?0.5 and 0<y<0.1) formed by providing nitrogen (N) into a MnGa alloy while adjusting a nitrogen amount. The perpendicular magnetic layer can be formed flat.
    Type: Application
    Filed: May 10, 2017
    Publication date: November 16, 2017
    Inventors: Shigeki TAKAHASHI, Yoshiaki SONOBE, Hiroaki SUKEGAWA, Hwachol LEE, Kazuhiro HONO, Seiji MITANI, Jun LIU
  • Patent number: 9715915
    Abstract: Magneto-resistive devices with lower power consumption and higher stability are provided. The magneto-resistive devices may include a pinned layer, a free layer and an insulating layer between the pinned layer and the free layer. The pinned layer, the free layer and the insulating layer may constitute a magnetic tunnel junction. The free layer may include a first magnetic layer and a second magnetic layer that has a Curie temperature lower than a Curie temperature of the first magnetic layer.
    Type: Grant
    Filed: October 26, 2015
    Date of Patent: July 25, 2017
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Eiji Kita, Yoshiaki Sonobe
  • Publication number: 20170117458
    Abstract: A magnetic tunnel junction device includes a Heusler alloy layer that has not only a perpendicular magnetic anisotropy characteristic, but also a half-metallicity characteristic. For example, the magnetic tunnel junction device includes at least one Heusler alloy layer and a barrier layer. The barrier layer is in contact with the Heusler alloy layer and has an insulating property. A compressive strain is exerted on the Heusler alloy layer in a direction parallel to an interface between the Heusler alloy layer and the barrier layer.
    Type: Application
    Filed: September 30, 2016
    Publication date: April 27, 2017
    Inventors: Yoshiaki SONOBE, Hiroyoshi ITOH
  • Patent number: 9424873
    Abstract: A method of manufacturing a perpendicular magnetic recording medium 100 that includes forming a magnetic recording layer 122 on a disk base 110, then forming a resist layer 130 on the magnetic recording layer, and a patterning step of processing the resist layer so as to vary the thickness of the resist layer partially, thereby forming a predetermined pattern having a recessed part and a projected part. Finally, the method includes implanting ions into a plurality of layers including the magnetic recording layer with the resist layer interposed. At the ion implanting step, (1) one or more of said plurality of layers to be implanted with ions is determined by selectively applying an energy amount to implant ions, and (2) a total amount of ions to be implanted into each of said one or more of said plurality of layers is determined by selectively applying said energy amount for a respective time period for said one or more of said plurality of layers.
    Type: Grant
    Filed: February 19, 2010
    Date of Patent: August 23, 2016
    Assignee: WD Media (Singapore) Pte. Ltd
    Inventors: Masanori Aniya, Yoshiaki Sonobe
  • Patent number: 9349944
    Abstract: A magnetic tunnel junction device includes: a first magnetic layer that has an easy axis vertical to a surface; a non-magnetic layer on the first magnetic layer; and a second magnetic layer that has an easy axis vertical to a surface on the non-magnetic layer, and an interface layer formed of a Heussler alloy between the non-magnetic layer and at least one of the first and second magnetic layers. The at least one of the first and second magnetic layers is formed of MnGa. A lattice constant of the interface layer parallel to a major surface thereof in a bulk state thereof is between a lattice constant of the non-magnetic layer parallel to a major surface thereof in a bulk state thereof and a lattice constant of the at least one of the first and second magnetic layers parallel to a major surface thereof in a bulk state thereof.
    Type: Grant
    Filed: December 22, 2014
    Date of Patent: May 24, 2016
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Shigeki Takahashi, Yoshiaki Sonobe, Koki Takanashi
  • Publication number: 20160125924
    Abstract: Magneto-resistive devices with lower power consumption and higher stability are provided. The magneto-resistive devices may include a pinned layer, a free layer and an insulating layer between the pinned layer and the free layer. The pinned layer, the free layer and the insulating layer may constitute a magnetic tunnel junction. The free layer may include a first magnetic layer and a second magnetic layer that has a Curie temperature lower than a Curie temperature of the first magnetic layer.
    Type: Application
    Filed: October 26, 2015
    Publication date: May 5, 2016
    Inventors: Eiji KITA, Yoshiaki Sonobe