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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Publication number: 20140159177Abstract: 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: February 18, 2014Publication date: June 12, 2014Applicants: WPI-AIMR, Tohoku University, Kabushiki Kaisha ToshibaInventors: 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: 8750666Abstract: An optical device having a plasmonic waveguide, in which the plasmonic waveguide has a layered structure of at least three layers that a ferromagnetic metal layer, a first dielectric layer, and a second dielectric layer are layered in this order, in which the first and second dielectric layers are layers that allow light to be transmitted therethrough, and in which a refractive index of the second dielectric layer is higher than a refractive index of the first dielectric layer; and an optical isolator, having the optical device.Type: GrantFiled: January 22, 2013Date of Patent: June 10, 2014Assignee: National Institute of Advanced Industrial Science and TechnologyInventors: Vadym Zayets, Koji Ando, Hidekazu Saito, Shinji Yuasa
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Patent number: 8705269Abstract: A magnetoresistive element according to an embodiment includes: a first and second magnetic layers having an easy axis of magnetization in a direction perpendicular to a film plane; and a first nonmagnetic layer interposed between the first and second magnetic layers, at least one of the first and second magnetic layers including a structure formed by stacking a first and second magnetic films, the second magnetic film being located closer to the first nonmagnetic layer, the second magnetic film including a structure formed by repeating stacking of a magnetic material layer and a nonmagnetic material layer at least twice, the nonmagnetic material layers of the second magnetic film containing at least one element selected from the group consisting of Ta, W, Hf, Zr, Nb, Mo, Ti, V, and Cr, one of the first and second magnetic layers having a magnetization direction that is changed by applying a current.Type: GrantFiled: September 14, 2011Date of Patent: April 22, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Toshihiko Nagase, Tadashi Kai, Makoto Nagamine, Katsuya Nishiyama, Eiji Kitagawa, Tadaomi Daibou, Koji Ueda, Hiroaki Yoda, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
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Patent number: 8680632Abstract: 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: December 2, 2011Date of Patent: March 25, 2014Assignees: 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: 20140024140Abstract: 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: ApplicationFiled: September 20, 2013Publication date: January 23, 2014Applicants: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, CANON ANELVA CORPORATIONInventors: David D. Djayaprawira, Koji Tsunekawa, Motonobu Nagai, Hiroki Maehara, Shinji Yamagata, Naoki Watanabe, Shinji Yuasa
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Publication number: 20130288397Abstract: According to one embodiment, a magnetoresistive effect element includes a first magnetic layer including perpendicular anisotropy to a film surface and an invariable magnetization direction, the first magnetic layer having a magnetic film including an element selected from a first group including Tb, Gd, and Dy and an element selected from a second group including Co and Fe, a second magnetic layer including perpendicular magnetic anisotropy to the film surface and a variable magnetization direction, and a nonmagnetic layer between the first magnetic layer and the second magnetic layer. The magnetic film includes amorphous phases and crystals whose particle sizes are 0.5 nm or more.Type: ApplicationFiled: July 1, 2013Publication date: October 31, 2013Inventors: Eiji Kitagawa, Tadaomi Daibou, Yutaka Hashimoto, Masaru Tokou, Tadashi Kai, Makato Nagamine, Toshihiko Nagase, Katsuya Nishiyama, Koji Ueda, Hiroaki Yoda, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
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Publication number: 20130228883Abstract: 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 14, 2013Publication date: September 5, 2013Applicants: National Institute of Advanced Industrial Science and Technology, Japan Science and Technology AgencyInventor: Shinji YUASA
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Patent number: 8521795Abstract: A random number generating device is constructed such that it has improved random number generation rate and allows for construction of compact circuit with ease. The random number generating device includes a magnetoresistive element that has three layers consisting of a magnetization free layer, an interlayer, and a magnetization fixed layer, and has at least two resistance values depending on arrangement of magnetization in the magnetization free layer and the magnetization fixed layer, wherein the magnetoresistive element is subjected to be applied with a magnetization current so that the inversion probability of the magnetization free layer assumes a value between 0 and 1, through which the resistance value of the magnetoresistive element is extracted as random numbers.Type: GrantFiled: March 24, 2008Date of Patent: August 27, 2013Assignee: National Institute of Advanced Industrial Science and TechnologyInventors: Akio Fukushima, Hitoshi Kubota, Kay Yakushiji, Shinji Yuasa, Koji Ando
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Patent number: 8502331Abstract: According to one embodiment, a magnetoresistive effect element includes a first magnetic layer including perpendicular anisotropy to a film surface and an invariable magnetization direction, the first magnetic layer having a magnetic film including an element selected from a first group including Tb, Gd, and Dy and an element selected from a second group including Co and Fe, a second magnetic layer including perpendicular magnetic anisotropy to the film surface and a variable magnetization direction, and a nonmagnetic layer between the first magnetic layer and the second magnetic layer. The magnetic film includes amorphous phases and crystals whose particle sizes are 0.5 nm or more.Type: GrantFiled: September 16, 2011Date of Patent: August 6, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Eiji Kitagawa, Tadaomi Daibou, Yutaka Hashimoto, Masaru Tokou, Tadashi Kai, Makoto Nagamine, Toshihiko Nagase, Katsuya Nishiyama, Koji Ueda, Hiroaki Yoda, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
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Patent number: 8405134Abstract: 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 20, 2012Date of Patent: March 26, 2013Assignees: Japan Science and Technology Agency, National Institute of Advanced Industrial Science and TechnologyInventor: Shinji Yuasa
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Patent number: 8394649Abstract: 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: January 3, 2008Date of Patent: March 12, 2013Assignees: Canaon Anelva Corporation, National Institute of Advanced Industrial Science and TechnologyInventors: David D. Djayaprawira, Koji Tsunekawa, Motonobu Nagai, Hiroki Maehara, Shinji Yamagata, Naoki Watanabe, Shinji Yuasa
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Patent number: 8378437Abstract: A magnetoresistive effect element includes a reference layer, a recording layer, and a nonmagnetic layer. The reference layer is made of a magnetic material, has an invariable magnetization which is perpendicular to a film surface. The recording layer is made of a magnetic material, has a variable magnetization which is perpendicular to the film surface. The nonmagnetic layer is arranged between the reference layer and the recording layer. A critical diameter which is determined by magnetic anisotropy, saturation magnetization, and switched connection of the recording layer and has a single-domain state as a unique stable state or a critical diameter which has a single-domain state as a unique stable state and is inverted while keeping the single-domain state in an inverting process is larger than an element diameter of the magnetoresistive effect element.Type: GrantFiled: October 9, 2008Date of Patent: February 19, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Nakayama, Kay Yakushiji, Sumio Ikegawa, Shinji Yuasa, Tadashi Kai, Toshihiko Nagase, Minoru Amano, Hisanori Aikawa, Tatsuya Kishi, Hiroaki Yoda
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Patent number: 8319263Abstract: 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 by the following steps. A single-crystalline MgO (001) substrate 11 is prepared. An epitaxial Fe(001) lower electrode (a first electrode) 17 with the thickness of 50 nm is grown on a MgO(001) seed layer 15 at room temperature, followed by annealing under ultrahigh vacuum (2×10?8 Pa) and at 350° C. A MgO(001) barrier layer 21 with the thickness of 2 nm 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) with the thickness of 10 nm is then formed on the MgO(001) barrier layer 21 at room temperature. This is successively followed by the deposition of a Co layer 21 with the thickness of 10 nm on the Fe(001) upper electrode (the second electrode) 23.Type: GrantFiled: September 30, 2010Date of Patent: November 27, 2012Assignees: Japan Science and Technology Agency, National Institute of Advanced Industrial Science and TechnologyInventor: Shinji Yuasa
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Publication number: 20120241881Abstract: 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: December 2, 2011Publication date: September 27, 2012Applicants: Tohoku University, KABUSHIKI KAISHA TOSHIBAInventors: 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: 8270198Abstract: A nonvolatile optical memory element in which a ferromagnetic body is provided on a semiconductor causes such a problem that in a case where magnetization of the ferromagnetic body is read by light, magneto-optical response becomes very small when the ferromagnetic body is small in volume. The present invention provides a memory element, a memory device, and a data reading method, each of which is applicable to data reading from a nonvolatile optical memory element. In a nonvolatile optical memory element having a structure in which a ferromagnetic body is provided on a semiconductor that is connected to an optical waveguide, electrons are injected into the semiconductor via the ferromagnetic body so that the electrons that are spin-polarized according to a magnetization direction of the ferromagnetic body are injected into the semiconductor, thereby enlarging a region in which a photomagnetic effect occurs effectively.Type: GrantFiled: July 27, 2010Date of Patent: September 18, 2012Assignee: National Institute of Advanced Industrial Science and TechnologyInventors: Vadym Zayets, Koji Ando, Shinji Yuasa, Hidekazu Saito
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Publication number: 20120161262Abstract: 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 20, 2012Publication date: June 28, 2012Applicants: National Institute of Advanced Industrial Science and Technology, Japan Science and Technology AgencyInventor: Shinji Yuasa
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Patent number: 8208292Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.Type: GrantFiled: January 3, 2012Date of Patent: June 26, 2012Assignees: Kabushiki Kaisha Toshiba, National Institute of Advanced Industrial Science and TechnologyInventors: Tadashi Kai, Katsuya Nishiyama, Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Tadaomi Daibou, Makoto Nagamine, Masahiko Nakayama, Naoharu Shimomura, Hiroaki Yoda, Kei Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
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Publication number: 20120099369Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.Type: ApplicationFiled: January 3, 2012Publication date: April 26, 2012Inventors: Tadashi KAI, Katsuya Nishiyama, Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Tadaomi Daibou, Makoto Nagamine, Masahiko Nakayama, Naoharu Shimomura, Hiroaki Yoda, Kei Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
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Publication number: 20120068285Abstract: According to one embodiment, a magnetoresistive effect element includes a first magnetic layer including perpendicular anisotropy to a film surface and an invariable magnetization direction, the first magnetic layer having a magnetic film including an element selected from a first group including Tb, Gd, and Dy and an element selected from a second group including Co and Fe, a second magnetic layer including perpendicular magnetic anisotropy to the film surface and a variable magnetization direction, and a nonmagnetic layer between the first magnetic layer and the second magnetic layer. The magnetic film includes amorphous phases and crystals whose particle sizes are 0.5 nm or more.Type: ApplicationFiled: September 16, 2011Publication date: March 22, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Eiji KITAGAWA, Tadaomi Daibou, Yutaka Hashimoto, Masaru Tokou, Tadashi Kai, Makoto Nagamine, Toshihiko Nagase, Katsuya Nishiyama, Koji Ueda, Hiroaki Yoda, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
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Publication number: 20120069640Abstract: A magnetoresistive element according to an embodiment includes: a first and second magnetic layers having an easy axis of magnetization in a direction perpendicular to a film plane; and a first nonmagnetic layer interposed between the first and second magnetic layers, at least one of the first and second magnetic layers including a structure formed by stacking a first and second magnetic films, the second magnetic film being located closer to the first nonmagnetic layer, the second magnetic film including a structure formed by repeating stacking of a magnetic material layer and a nonmagnetic material layer at least twice, the nonmagnetic material layers of the second magnetic film containing at least one element selected from the group consisting of Ta, W, Hf, Zr, Nb, Mo, Ti, V, and Cr, one of the first and second magnetic layers having a magnetization direction that is changed by applying a current.Type: ApplicationFiled: September 14, 2011Publication date: March 22, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Toshihiko Nagase, Tadashi Kai, Makoto Nagamine, Katsuya Nishiyama, Eiji Kitagawa, Tadaomi Daibou, Koji Ueda, Hiroaki Yoda, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando