Patents by Inventor Hideo Ohno

Hideo Ohno 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: 20140205862
    Abstract: Provided are a magneto resistive effect element with a stable magnetization direction perpendicular to a film plane and with a controlled magnetoresistance ratio, and a magnetic memory using the magneto resistive effect element. Ferromagnetic layers 106 and 107 of the magneto resistive effect element are formed from a ferromagnetic material containing at least one type of 3d transition metal such that the magnetoresistance ratio is controlled, and the film thickness of the ferromagnetic layers is controlled on an atomic layer level such that the magnetization direction is changed from a direction in the film plane to a direction perpendicular to the film plane.
    Type: Application
    Filed: March 25, 2014
    Publication date: July 24, 2014
    Applicant: Tohoku University
    Inventors: Hideo Ohno, Shoji Ikeda, Fumihiro Matsukura, Masaki Endoh, Shun Kanai, Hiroyuki Yamamoto, Katsuya Miura
  • Publication number: 20140097509
    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: Application
    Filed: April 19, 2012
    Publication date: April 10, 2014
    Applicant: TOHOKU UNIVERSITY
    Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi
  • Publication number: 20130288398
    Abstract: [Object] To provide a method of manufacturing a perpendicular magnetization-type magnetic element, which does not need a step of depositing MgO. [Solving Means] The method of manufacturing a magnetoresistive element 1 according to the present invention includes laminating a first layer 30 on a base 10, the first layer 30 including a material containing at least one of Co, Ni, and Fe. Next, a second layer 40 is laminated on the first layer 30, the second layer 40 including Mg. Next, the Mg in the second layer 40 is oxidized to form MgO by applying an oxidation treatment to a laminated body including the first layer 30 and the second layer 40. Next, the second layer 40 is crystallized by applying a heat treatment to the laminated body, and the first layer 30 is caused to be perpendicularly magnetized. According to the manufacturing method, it is possible to manufacture a perpendicular magnetization-type CoFeB—MgO magnetic element without causing a problem arising from the deposition of MgO.
    Type: Application
    Filed: December 20, 2011
    Publication date: October 31, 2013
    Applicants: TOHOKU UNIVERSITY, ULVAC, INC.
    Inventors: Hiroki Yamamoto, Tadashi Morita, Hideo Ohno, Shoji Ikeda
  • Publication number: 20130141966
    Abstract: Provided are a magnetoresistance effect element with a stable magnetization direction perpendicular to film plane and a controlled magnetoresistance ratio, in which writing can be performed by magnetic domain wall motion, and a magnetic memory including the magnetoresistance effect element. The magnetoresistance ratio is controlled by forming a ferromagnetic layer of the magnetoresistance effect element from a ferromagnetic material including at least one type of 3d transition metal or a Heusler alloy. The magnetization direction is changed from a direction in the film plane to a direction perpendicular to the film plane by controlling the film thickness of the ferromagnetic layer on an atomic layer level.
    Type: Application
    Filed: May 26, 2011
    Publication date: June 6, 2013
    Inventors: Hideo Ohno, Shoji Ikeda, Fumihiro Matsukura, Masaki Endoh, Shun Kanai, Katsuya Miura, Hiroyuki Yamamoto
  • Publication number: 20130107616
    Abstract: A magnetoresistive effect element is provided that exhibits a low writing current density while maintaining a high TMR ratio. A laminated structure of a second ferromagnetic layer/a non-magnetic layer/a first ferromagnetic layer is employed as a recording layer. A material of bcc crystalline structure, such as CoFeB, is employed as a second ferromagnetic layer being in contact with MgO barrier layer. A material whose anisotropy field Hk? in the perpendicular direction is large and that satisfies the relationship of 2?rMs<Hk?<4?Ms is employed as a first ferromagnetic layer. Although a magnetic easy axis of the first ferromagnetic layer lies in-plane, it has a high perpendicular anisotropy field of half or more of the demagnetizing field in the perpendicular direction. Therefore, the effective demagnetizing field in the perpendicular direction is reduced, and a writing current density can be reduced.
    Type: Application
    Filed: July 9, 2010
    Publication date: May 2, 2013
    Inventors: Hideo Ohno, Shoji Ikeda, Hiroyuki Yamamoto, Kenchi Ito, Hiromasa Takahashi
  • Publication number: 20130094284
    Abstract: Provided are a magneto resistive effect element with a stable magnetization direction perpendicular to a film plane and with a controlled magnetoresistance ratio, and a magnetic memory using the magneto resistive effect element. Ferromagnetic layers 106 and 107 of the magneto resistive effect element are formed from a ferromagnetic material containing at least one type of 3d transition metal such that the magnetoresistance ratio is controlled, and the film thickness of the ferromagnetic layers is controlled on an atomic layer level such that the magnetization direction is changed from a direction in the film plane to a direction perpendicular to the film plane.
    Type: Application
    Filed: May 31, 2011
    Publication date: April 18, 2013
    Inventors: Hideo Ohno, Shoji Ikeda, Fumihiro Matsukura, Masaki Endoh, Shun Kanai, Hiroyuki Yamamoto, Katsuya Miura
  • Publication number: 20130058156
    Abstract: A relation between a drive current of a selection transistor of a magnetic memory and a threshold magnetization switching current of the magnetoresistance effect element is optimized. In order to optimize the relation between the drive current of the selection transistor and the threshold magnetization switching current of the magnetoresistance effect element 101 of the magnetic memory cell, a mechanism 601-604 for dropping the threshold magnetization switching current on “1” writing is provided that applies a magnetic field that is in the inverse direction of the pinned layer to the recording layer of the magnetoresistance effect element.
    Type: Application
    Filed: February 17, 2011
    Publication date: March 7, 2013
    Inventors: Hideo Ohno, Shoji Ikeda, Katsuya Miura, Kazuo Ono
  • Publication number: 20130028013
    Abstract: Provided is a magnetoresistive effect element which uses a perpendicularly magnetized material and has a high TMR ratio. Intermediate layers 31, 32 composed of an element metal having a melting point of 1600° C. or an alloy containing the metal on an outside of a structure consisting of a CoFeB layer 41, an MgO barrier layer 10, and a CoFeB layer 42. By inserting the intermediate layers 31, 32, crystallization of the CoFeB layer during annealing is advanced from an MgO (001) crystal side, so that the CoFeB layer has a crystalline orientation in bcc (001).
    Type: Application
    Filed: January 25, 2011
    Publication date: January 31, 2013
    Inventors: Shoji Ikeda, Hideo Ohno, Hiroyuki Yamamoto, Kenchi Ito, Hiromasa Takahashi
  • Publication number: 20120320666
    Abstract: There is provided a magnetoresistive element whose magnetization direction is stable in a direction perpendicular to the film surface and whose magnetoresistance ratio is controlled, as well as magnetic memory using such a magnetoresistive element. By having the material of a ferromagnetic layer forming the magnetoresistive element comprise a ferromagnetic material containing at least one type of 3d transition metal, or a Heusler alloy, to control the magnetoresistance ratio, and by controlling the thickness of the ferromagnetic layer on an atomic layer level, the magnetization direction is changed from being in-plane with the film surface to being perpendicular to the film surface.
    Type: Application
    Filed: February 14, 2011
    Publication date: December 20, 2012
    Applicants: Tohoku University, Hitachi, Ltd.
    Inventors: Hideo Ohno, Shoji Ikeda, Fumihiro Matsukura, Masaki Endoh, Shun Kanai, Katsuya Miura, Hiroyuki Yamamoto
  • Patent number: 8331140
    Abstract: The present invention provides a current injection-type magnetic domain wall-motion device which requires no external magnetic field for reversing the magnetization direction of a ferromagnetic body and which has low power consumption. The current injection-type magnetic domain wall-motion device includes a microjunction structure including two magnetic bodies (a first magnetic body 1 and a second magnetic body 2) having magnetization directions antiparallel to each other and a third magnetic body 3 sandwiched therebetween. The magnetization direction of the device is controlled in such a manner that a pulse current (a current density of 104-107 A/cm2) is applied across junction interfaces present in the microjunction structure such that a magnetic domain wall is moved by the interaction between the magnetic domain wall and the current in the same direction as that of the current or in the direction opposite to that of the current.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: December 11, 2012
    Assignees: Japan Science and Technology Agency, Tohoku University
    Inventors: Hideo Ohno, Fumihiro Matsukura, Daichi Chiba, Michihiko Yamanouchi
  • Publication number: 20120300543
    Abstract: In magnetic tunnel junctions manufactured with use of a ferromagnetic material having perpendicular magnetic anisotropy, a difference in record retention time depending on stored information due to an imbalance in thermal stability between a parallel state and an anti-parallel state of magnetization, which correspond to bit information, is alleviated. A reference layer and a recording layer which constitute a magnetic tunnel junction are made different in area from each other so as to correct the difference in record retention time corresponding to stored information.
    Type: Application
    Filed: May 24, 2012
    Publication date: November 29, 2012
    Inventors: Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi, Hideo Sato, Katsuya Miura
  • Patent number: 8310867
    Abstract: A nonvolatile solid state magnetic memory with a ultra-low power consumption and a recording method thereof, the memory including a magnetic material having a magnetic anisotropy that can be changed by increasing or decreasing a carrier concentration, wherein a direction of an easy axis of magnetization, in which the magnetization is oriented easily, is controlled by increasing or decreasing the carrier concentration. The nonvolatile solid state magnetic memory including a recording layer of a magnetic material, and a recording method thereof, in which a carrier (electron or hole) concentration in the recording layer is increased and/or decreased, whereby the magnetization is rotated or reversed and the recording operation is performed.
    Type: Grant
    Filed: October 3, 2008
    Date of Patent: November 13, 2012
    Assignees: Japan Science and Technology Agency, Tohoku University
    Inventors: Hideo Ohno, Fumihiro Matsukura, Daichi Chiba
  • Patent number: 8274818
    Abstract: Provided is a high-speed and ultra-low-power-consumption nonvolatile memory having a high temperature stability at a zero magnetic field. In a tunnel magnetoresistive film constituting a nonvolatile magnetic memory that employs a writing method using a spin-transfer torque, an insulating layer and a nonmagnetic conductive layer are stacked above a ferromagnetic free layer.
    Type: Grant
    Filed: August 5, 2008
    Date of Patent: September 25, 2012
    Assignees: Tohoku University, Hitachi, Ltd.
    Inventors: Hideo Ohno, Shoji Ikeda, Young Min Lee, Jun Hayakawa
  • Patent number: 8217477
    Abstract: Provided is a reliable nonvolatile memory with a lower power consumption. A ferromagnetic interconnection which is magnetized antiparallel or parallel to a magnetization direction of a ferromagnetic pinned layer in a giant magnetoresistive device or a tunnel magnetoresistive device constituting the magnetic memory cell, is connected to a ferromagnetic free layer with a non-magnetic layer being interposed in between, the ferromagnetic free layer serving as a recording layer. Thereby, the magnetization of the recording layer is switched by use of a spin transfer torque.
    Type: Grant
    Filed: December 23, 2008
    Date of Patent: July 10, 2012
    Assignees: Hitachi, Ltd., Tohoku University
    Inventors: Hideo Ohno, Shoji Ikeda, Jun Hayakawa
  • Publication number: 20120132908
    Abstract: In a thin film transistor, a gate insulating layer is formed on a gate electrode formed on an insulating substrate. Formed on the gate insulating layer is a semiconductor layer. Formed on the semiconductor layer are a source electrode and a drain electrode. A protective layer covers them, so that the semiconductor layer is blocked from an atmosphere. The semiconductor layer (active layer) is made of, e.g., a semiconductor containing polycrystalline ZnO to which, e.g., a group V element is added. This allows practical use of a semiconductor device which has an active layer made of zinc oxide and which includes an protective layer for blocking the active layer from an atmosphere.
    Type: Application
    Filed: February 3, 2012
    Publication date: May 31, 2012
    Applicants: SHARP KABUSHIKI KAISHA
    Inventors: Toshinori Sugihara, Hideo Ohno, Masashi Kawasaki
  • Patent number: 8173487
    Abstract: A thin-film transistor (1) of the present invention includes an insulating substrate (2), a gate electrode (3) which has a predetermined shape and is formed on the insulating substrate (2), a gate insulating film (4) formed on the gate electrode (3), and a semiconductor layer (5) which is polycrystalline ZnO and is formed on the gate insulating film (4). The semiconductor layer (5) is immersed in a solution in which impurities are dissolved so that the impurities are selectively added to a grain boundary part of the polycrystalline ZnO film. Subsequently, a source electrode (6) and a drain electrode (7) are formed so as to have a predetermined shape. Next, a protection layer (8) is formed on the source electrode (6) and the drain electrode (7). Thus, a thin-film transistor which has a good subthreshold characteristic and has a zinc oxide film as a base of an active layer can be realized.
    Type: Grant
    Filed: April 1, 2008
    Date of Patent: May 8, 2012
    Assignees: Sharp Kabushiki Kaisha, Tohoku University
    Inventors: Masao Urayama, Masashi Kawasaki, Hideo Ohno
  • Patent number: 8093589
    Abstract: In a thin film transistor (1), a gate insulating layer (4) is formed on a gate electrode (3) formed on an insulating substrate (2). Formed on the gate insulating layer (4) is a semiconductor layer (5). Formed on the semiconductor layer (5) are a source electrode (6) and a drain electrode (7). A protective layer (8) covers them, so that the semiconductor layer (5) is blocked from an atmosphere. The semiconductor layer (5) (active layer) is made of, e.g., a semiconductor containing polycrystalline ZnO to which, e.g., a group V element is added. This allows practical use of a semiconductor device which has an active layer made of zinc oxide and which includes an protective layer for blocking the active layer from an atmosphere.
    Type: Grant
    Filed: June 14, 2004
    Date of Patent: January 10, 2012
    Assignees: Sharp Kabushiki Kaisha
    Inventors: Toshinori Sugihara, Hideo Ohno, Masashi Kawasaki
  • Publication number: 20110175090
    Abstract: In a thin film transistor, a gate insulating layer is formed on a gate electrode formed on an insulating substrate. Formed on the gate insulating layer is a semiconductor layer. Formed on the semiconductor layer are a source electrode and a drain electrode. A protective layer covers them, so that the semiconductor layer is blocked from an atmosphere. The semiconductor layer (active layer) is made of, e.g., a semiconductor containing polycrystalline ZnO to which, e.g., a group V element is added. This allows practical use of a semiconductor device which has an active layer made of zinc oxide and which includes an protective layer for blocking the active layer from an atmosphere.
    Type: Application
    Filed: March 28, 2011
    Publication date: July 21, 2011
    Applicants: Sharp Kabushiki Kaisha, Hideo Ohno, Masashi Kawasaki
    Inventors: Toshinori Sugihara, Hideo Ohno, Masashi Kawasaki
  • Patent number: 7894244
    Abstract: Provided is a high-speed, super-low-power-consumption nonvolatile memory with a high thermal stability. A nonvolatile magnetic memory is equipped with high-output tunnel magnetic resistance devices to each of which a free layer with a high thermal stability is applied, while a writing method by spin transfer torque is applied to the memory. The tunnel magnetic resistance device has a free layer including a first ferromagnetic film and the second ferromagnetic film each of which has a body center cubic structure and each of which contains Co, Fe and B. The free layer, additionally, includes a first non-magnetic layer. The tunnel magnetic resistance device has a layered structure formed of the free layer and a pinned layer with a MgO insulating film with a (100) orientation rock-salt structure interposed in between.
    Type: Grant
    Filed: April 25, 2007
    Date of Patent: February 22, 2011
    Assignees: Hitachi, Ltd., Tohoku University
    Inventors: Jun Hayakawa, Hideo Ohno, Shoji Ikeda, Young Min Lee
  • Patent number: 7838953
    Abstract: A magnetic memory cell and a magnetic random access memory that are highly reliable and low-power consuming. An upper electrode having a connecting area smaller than the area of a ferromagnetic free layer of a magnetic memory cell is connected to the ferromagnetic free layer. A current is applied to produce an uneven magnetic field over the magnetic memory cell, whereby spin-transfer torque magnetization reversal can be realized with low current and at small write error rate.
    Type: Grant
    Filed: October 4, 2007
    Date of Patent: November 23, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Hideo Ohno, Shoji Ikeda, Jun Hayakawa