Patents by Inventor Shinji Yuasa
Shinji Yuasa 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).
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Patent number: 10319902Abstract: Some embodiments are directed to a magnetoresistive device, including a free layer having an easy magnetization direction in a perpendicular direction or in an in-plane direction; a fixed layer having the easy magnetization direction which is in the perpendicular direction when the easy magnetization direction of the free layer is in the perpendicular direction or in the in-plane direction when the easy magnetization direction of the free layer is in the in-plane direction; and a non-magnetic layer disposed between the free layer and the fixed layer.Type: GrantFiled: February 14, 2018Date of Patent: June 11, 2019Assignee: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: Rie Matsumoto, Hiroko Arai, Shinji Yuasa, Hiroshi Imamura
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Publication number: 20180302035Abstract: The present invention provides a high-frequency phase-locked oscillation circuit having an extremely narrow peak width and a stable frequency so that a high-frequency wave that is oscillated by the MR element solves a problem of a large peak width of oscillation spectrum.Type: ApplicationFiled: April 27, 2016Publication date: October 18, 2018Inventors: Shingo Tamaru, Hitoshi Kubota, Akio Fukushima, Shinji Yuasa
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Publication number: 20180233659Abstract: Some embodiments are directed to a magnetoresistive device, including a free layer having an easy magnetization direction in a perpendicular direction or in an in-plane direction; a fixed layer having the easy magnetization direction which is in the perpendicular direction when the easy magnetization direction of the free layer is in the perpendicular direction or in the in-plane direction when the easy magnetization direction of the free layer is in the in-plane direction; and a non-magnetic layer disposed between the free layer and the fixed layer.Type: ApplicationFiled: February 14, 2018Publication date: August 16, 2018Inventors: Rie MATSUMOTO, Hiroko ARAI, Shinji YUASA, Hiroshi IMAMURA
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Publication number: 20180158525Abstract: According to one embodiment, a resistance change type memory includes: a variable resistance element connected between first and second bit lines; a write control circuit including first and second transistors with terminals connected to the first and second bit lines, respectively, and controlling write to the variable resistance element; a first interconnect supplied with a first voltage and connected to the first bit line via the first transistor; and a second interconnect supplied with a second voltage higher than the first voltage, and connected to the first bit line via the second transistor. The write control circuit supplies the second voltage to the first bit line with a first pulse width via the second transistor in the ON state after supplying the first voltage to the first bit line via the first transistor.Type: ApplicationFiled: November 30, 2017Publication date: June 7, 2018Applicant: National Institute of Advanced Science and TechnologyInventors: Takayuki Nozaki, Yoshishige Suzuki, Shinji Yuasa, Yoichi Shiota, Takurou Ikeura, Hiroki Noguchi, Kazutaka Ikegami
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Publication number: 20180151214Abstract: A non-collinear magnetoresistive device, includes: a free layer; a fixed layer; and a non-magnetic layer disposed between the free layer and the fixed layer, wherein the fixed layer has an easy magnetization direction in an in-plane direction or in a perpendicular direction, the free layer satisfies at room temperature expressions (1) and (2) below: ERT?1.66×10?19 J??(1) V?5×104 nm3??(2) where ERT=(Ku1,eff+Ku2+Ku1,eff2/4Ku2)×V, Ku1,eff: an effective first-order anisotropy constant, Ku2: a second-order anisotropy constant, and V: a volume, and wherein the free layer is in a cone magnetization state.Type: ApplicationFiled: May 19, 2016Publication date: May 31, 2018Inventors: Rie MATSUMOTO, Hiroko ARAI, Shinji YUASA, Hiroshi IMAMURA
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Publication number: 20170155042Abstract: The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.Type: ApplicationFiled: February 9, 2017Publication date: June 1, 2017Inventor: Shinji YUASA
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Patent number: 9620189Abstract: A magnetic memory according to an embodiment includes at least one MTJ element, the MTJ element including: a magnetic multilayer structure including a first magnetic layer in which a direction of magnetization is fixed, a second magnetic layer in which a direction of magnetization is changeable, and a tunnel barrier layer located between the first and second magnetic layers; a first electrode provided on a first surface of the magnetic multilayer structure; a second electrode provided on a second surface of the magnetic multilayer structure; an insulating film provided on a side surface of the magnetic multilayer structure; and a control electrode provided on the side surface of the magnetic multilayer structure with the insulating film located therebetween, a voltage being applied to the control electrode in a read operation, which increases an energy barrier for changing the magnetization of the second magnetic layer.Type: GrantFiled: November 20, 2015Date of Patent: April 11, 2017Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Naoharu Shimomura, Eiji Kitagawa, Minoru Amano, Daisuke Saida, Kay Yakushiji, Takayuki Nozaki, Shinji Yuasa, Akio Fukushima, Hiroshi Imamura, Hitoshi Kubota
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Patent number: 9608198Abstract: The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.Type: GrantFiled: August 27, 2015Date of Patent: March 28, 2017Assignees: JAPAN SCIENCE AND TECHNOLOGY AGENCY, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventor: Shinji Yuasa
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Patent number: 9437810Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer having a variable magnetization direction; a second magnetic layer having an invariable magnetization direction; and a tunnel barrier layer provided between the first magnetic layer and the second magnetic layer and including an MgFeO film, wherein the MgFeO film contains at least one element selected from a group consisting of Ti, V, Mn, and Cu.Type: GrantFiled: February 28, 2014Date of Patent: September 6, 2016Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Eiji Kitagawa, Takao Ochiai, Kay Yakushiji, Makoto Konoto, Hitoshi Kubota, Shinji Yuasa, Takayuki Nozaki, Akio Fukushima
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Publication number: 20160118098Abstract: A magnetic memory according to an embodiment includes at least one MTJ element, the MTJ element including: a magnetic multilayer structure including a first magnetic layer in which a direction of magnetization is fixed, a second magnetic layer in which a direction of magnetization is changeable, and a tunnel barrier layer located between the first and second magnetic layers; a first electrode provided on a first surface of the magnetic multilayer structure; a second electrode provided on a second surface of the magnetic multilayer structure; an insulating film provided on a side surface of the magnetic multilayer structure; and a control electrode provided on the side surface of the magnetic multilayer structure with the insulating film located therebetween, a voltage being applied to the control electrode in a read operation, which increases an energy barrier for changing the magnetization of the second magnetic layer.Type: ApplicationFiled: November 20, 2015Publication date: April 28, 2016Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Naoharu SHIMOMURA, Eiji KITAGAWA, Minoru AMANO, Daisuke SAIDA, Kay YAKUSHIJI, Takayuki NOZAKI, Shinji YUASA, Akio FUKUSHIMA, Hiroshi IMAMURA, Hitoshi KUBOTA
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Publication number: 20160020385Abstract: The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.Type: ApplicationFiled: August 27, 2015Publication date: January 21, 2016Inventor: Shinji YUASA
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Patent number: 9230628Abstract: A magnetic memory according to an embodiment includes at least one MTJ element, the MTJ element including: a magnetic multilayer structure including a first magnetic layer in which a direction of magnetization is fixed, a second magnetic layer in which a direction of magnetization is changeable, and a tunnel barrier layer located between the first and second magnetic layers; a first electrode provided on a first surface of the magnetic multilayer structure; a second electrode provided on a second surface of the magnetic multilayer structure; an insulating film provided on a side surface of the magnetic multilayer structure; and a control electrode provided on the side surface of the magnetic multilayer structure with the insulating film located therebetween, a voltage being applied to the control electrode in a read operation, which increases an energy barrier for changing the magnetization of the second magnetic layer.Type: GrantFiled: March 6, 2014Date of Patent: January 5, 2016Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Naoharu Shimomura, Eiji Kitagawa, Minoru Amano, Daisuke Saida, Kay Yakushiji, Takayuki Nozaki, Shinji Yuasa, Akio Fukushima, Hiroshi Imamura, Hitoshi Kubota
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Patent number: 9219227Abstract: A magnetoresistive element according to an embodiment includes: a base layer; a first magnetic layer formed on the base layer, and including a first magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the first magnetic film including MnxGa100-x (45?x<64 atomic %); a first nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the first nonmagnetic layer, and including a second magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the second magnetic film including MnyGa100-y (45?y<64 atomic %). The first and second magnetic layers include different Mn composition rates from each other, a magnetization direction of the first magnetic layer is changeable by a current flowing between the first magnetic layer and the second magnetic layer via the first nonmagnetic layer.Type: GrantFiled: November 20, 2014Date of Patent: December 22, 2015Assignees: KABUSHIKI KAISHA TOSHIBA, WPI-AIMR, Tohoku UniversityInventors: Tadaomi Daibou, Junichi Ito, Tadashi Kai, Minoru Amano, Hiroaki Yoda, Terunobu Miyazaki, Shigemi Mizukami, Koji Ando, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Akio Fukushima, Taro Nagahama, Takahide Kubota
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Publication number: 20150280111Abstract: A magnetic multilayer film, includes a nonmagnetic layer including a single- or poly-crystalline magnesium oxide in which a (001) crystal plane is preferentially oriented, a very thin layer including an oxide of a 3d transition metal element, and a very thin ferromagnetic layer, laminated in sequence starting on a substrate side.Type: ApplicationFiled: August 27, 2013Publication date: October 1, 2015Inventors: Shinji Yuasa, Takayuki Nozaki
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Patent number: 9123463Abstract: The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.Type: GrantFiled: February 14, 2013Date of Patent: September 1, 2015Assignees: JAPAN SCIENCE AND TECHNOLOGY AGENCY, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventor: Shinji Yuasa
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Patent number: 9087980Abstract: A magnetoresistive element according to an embodiment includes: a base layer; a first magnetic layer formed on the base layer, and including a first magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the first magnetic film including MnxGa100-x (45?x<64 atomic %); a first nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the first nonmagnetic layer, and including a second magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the second magnetic film including MnyGa100-y (45?y<64 atomic %). The first and second magnetic layers include different Mn composition rates from each other, a magnetization direction of the first magnetic layer is changeable by a current flowing between the first magnetic layer and the second magnetic layer via the first nonmagnetic layer.Type: GrantFiled: February 18, 2014Date of Patent: July 21, 2015Assignees: KABUSHIKI KAISHA TOSHIBA, WPI-AIMR, Tohoku UniversityInventors: Tadaomi Daibou, Junichi Ito, Tadashi Kai, Minoru Amano, Hiroaki Yoda, Terunobu Miyazaki, Shigemi Mizukami, Koji Ando, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Akio Fukushima, Taro Nagahama, Takahide Kubota
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Publication number: 20150076635Abstract: A magnetoresistive element according to an embodiment includes: a base layer; a first magnetic layer formed on the base layer, and including a first magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the first magnetic film including MnxGa100-x (45?x<64 atomic %); a first nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the first nonmagnetic layer, and including a second magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the second magnetic film including MnyGa100-y (45?y<64 atomic %). The first and second magnetic layers include different Mn composition rates from each other, a magnetization direction of the first magnetic layer is changeable by a current flowing between the first magnetic layer and the second magnetic layer via the first nonmagnetic layer.Type: ApplicationFiled: November 20, 2014Publication date: March 19, 2015Applicants: KABUSHIKI KAISHA TOSHIBA, WPI-AIMR, Tohoku UniversityInventors: Tadaomi DAIBOU, Junichi ITO, Tadashi KAI, Minoru AMANO, Hiroaki YODA, Terunobu MIYAZAKI, Shigemi MIZUKAMI, Koji ANDO, Kay YAKUSHIJI, Shinji YUASA, Hitoshi KUBOTA, Akio FUKUSHIMA, Taro NAGAHAMA, Takahide KUBOTA
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Patent number: 8934290Abstract: A magnetoresistance effect device including a multilayer structure having a pair of ferromagnetic layers and a barrier layer positioned between them, wherein at least one ferromagnetic layer has at least the part contacting the barrier layer made amorphous and the barrier layer is an MgO layer having a highly oriented texture structure.Type: GrantFiled: September 20, 2013Date of Patent: January 13, 2015Assignees: Canon Anelva Corporation, National Institute of Advanced Industrial Science Nad TechnologyInventors: David D. Djayaprawira, Koji Tsunekawa, Motonobu Nagai, Hiroki Maehara, Shinji Yamagata, Naoki Watanabe, Shinji Yuasa
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Publication number: 20140269038Abstract: A magnetic memory according to an embodiment includes at least one MTJ element, the MTJ element including: a magnetic multilayer structure including a first magnetic layer in which a direction of magnetization is fixed, a second magnetic layer in which a direction of magnetization is changeable, and a tunnel barrier layer located between the first and second magnetic layers; a first electrode provided on a first surface of the magnetic multilayer structure; a second electrode provided on a second surface of the magnetic multilayer structure; an insulating film provided on a side surface of the magnetic multilayer structure; and a control electrode provided on the side surface of the magnetic multilayer structure with the insulating film located therebetween, a voltage being applied to the control electrode in a read operation, which increases an energy barrier for changing the magnetization of the second magnetic layer.Type: ApplicationFiled: March 6, 2014Publication date: September 18, 2014Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Naoharu SHIMOMURA, Eiji KITAGAWA, Minoru AMANO, Daisuke SAIDA, Kay YAKUSHIJI, Takayuki NOZAKI, Shinji YUASA, Akio FUKUSHIMA, Hiroshi IMAMURA, Hitoshi KUBOTA
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Publication number: 20140264673Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer having a variable magnetization direction; a second magnetic layer having an invariable magnetization direction; and a tunnel barrier layer provided between the first magnetic layer and the second magnetic layer and including an MgFeO film, wherein the MgFeO film contains at least one element selected from a group consisting of Ti, V, Mn, and Cu.Type: ApplicationFiled: February 28, 2014Publication date: September 18, 2014Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Eiji Kitagawa, Takao Ochiai, Kay Yakushiji, Makoto Konoto, Hitoshi Kubota, Shinji Yuasa, Takayuki Nozaki, Akio Fukushima