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: 8107281Abstract: 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: September 10, 2010Date of Patent: January 31, 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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Patent number: 8013408Abstract: A magneto-resistive device has a magnetic free layer (33), a magnetic pinned layer (31) having a magnetic moment larger than that of the magnetic free layer, and an intermediate layer (32) provided between the magnetic free layer and the magnetic pinned layer. The negative-resistance device is characterized in that the negative-resistance device shows negative resistance by making the magnetic free layer continually change the magnetization direction along with the increase of the voltage which is applied to a magneto-resistive device so that electrons flow into the negative-resistance device from a magnetic free layer side.Type: GrantFiled: May 19, 2009Date of Patent: September 6, 2011Assignee: Canon Anelva CorporationInventors: Hiroki Maehara, Hitoshi Kubota, Akio Fukushima, Shinji Yuasa, Yoshishige Suzuki, Yoshinori Nagamine
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Publication number: 20110094875Abstract: 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: January 3, 2011Publication date: April 28, 2011Applicants: CANON 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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Publication number: 20110073970Abstract: 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: September 10, 2010Publication date: March 31, 2011Inventors: 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: 20110031570Abstract: 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: ApplicationFiled: September 30, 2010Publication date: February 10, 2011Inventor: Shinji Yuasa
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Patent number: 7884403Abstract: 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: March 10, 2005Date of Patent: February 8, 2011Assignees: Japan Science and Technology Agency, National Institute of Advanced Industrial Science and TechnologyInventor: Shinji Yuasa
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Publication number: 20110026296Abstract: 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: ApplicationFiled: July 27, 2010Publication date: February 3, 2011Applicant: National Institute of Advanced Industrial Science and TechnologyInventors: Vadym Zayets, Koji Ando, Shinji Yuasa, Hidekazu Saito
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Patent number: 7764136Abstract: A strip line integrated microwave generating element and a microwave detecting element comprises a signal electrode and a ground electrode. The element has a magnetic tunnel junction structure which includes a magnetization fixed layer, a MgO tunnel barrier layer, and a magnetization free layer. The magnetization free layer is 200 nm square or smaller in a cross-sectional area. The magnetization fixed layer is in contact with either one of the signal electrode and the ground electrode while the magnetization free layer of the element being in contact with the other. The element is smaller than the electrodes and mounted on a part of the signal electrode or the ground electrode. A MR ratio of the element is of 100% or more. A resistance value of the element is from 50? to 300?. The resistance of the element is matched with an impedance of the microwave transmission line.Type: GrantFiled: March 17, 2006Date of Patent: July 27, 2010Assignee: Japan Science and Technology AgencyInventors: Yoshishige Suzuki, Shinji Yuasa, Akio Fukushima, Ashwin Tulapurkar
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Publication number: 20100181632Abstract: 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: ApplicationFiled: March 23, 2010Publication date: July 22, 2010Inventor: Shinji Yuasa
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Publication number: 20100131578Abstract: 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: ApplicationFiled: March 24, 2008Publication date: May 27, 2010Inventors: Akio Fukushima, Hitoshi Kubota, Kay Yakushiji, Shinji Yuasa, Koji Ando
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Publication number: 20100055502Abstract: A tunneling magnetoresistive device includes: a fixed layer that includes a ferromagnetic material; a tunneling insulating film that is provided in contact with the fixed layer; and a free layer that includes a first ferromagnetic film provided in contact with the tunneling insulating film, a second ferromagnetic film whose magnetization is coupled parallel to the magnetization of the first ferromagnetic film, and a conductive film interposed between the first ferromagnetic film and the second ferromagnetic film.Type: ApplicationFiled: August 26, 2009Publication date: March 4, 2010Applicant: Nat Inst of Adv Industrial Sci and TechInventors: Hitoshi KUBOTA, Akio FUKUSHIMA, Kei YAKUSHIJI, Shinji YUASA, Koji ANDO, Satoshi YAKATA
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Publication number: 20090322419Abstract: An amplifying apparatus includes a magneto-resistive device which has a magnetic free layer, a magnetic pinned layer having a magnetic moment larger than that of the magnetic free layer, and an intermediate layer provided in between the magnetic free layer and the magnetic pinned layer. The amplifying apparatus has a first electrode layer provided in a magnetic free layer side of the magneto-resistive device, and a second electrode layer provided in a magnetic pinned layer side of the magneto-resistive device. The amplifying apparatus further includes a direct-current bias power-source for applying a direct-current bias to the magneto-resistive device, and a load resistor. The amplifying apparatus continually causes the change of a magnetization direction of the magnetic free layer to make the magneto-resistive device show negative resistance, and thereby amplifies an input signal.Type: ApplicationFiled: July 20, 2009Publication date: December 31, 2009Applicant: CANON ANELVA CORPORATIONInventors: Hiroki Maehara, Hitoshi Kubota, Akio Fukushima, Shinji Yuasa, Yoshishige Suzuki, Yoshinori Nagamine
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Publication number: 20090261436Abstract: A magneto-resistive device has a magnetic free layer (33), a magnetic pinned layer (31) having a magnetic moment larger than that of the magnetic free layer, and an intermediate layer (32) provided between the magnetic free layer and the magnetic pinned layer. The negative-resistance device is characterized in that the negative-resistance device shows negative resistance by making the magnetic free layer continually change the magnetization direction along with the increase of the voltage which is applied to a magneto-resistive device so that electrons flow into the negative-resistance device from a magnetic free layer side.Type: ApplicationFiled: May 19, 2009Publication date: October 22, 2009Applicant: CANON ANELVA CORPORATIONInventors: Hiroki Maehara, Hitoshi Kubota, Akio Fukushima, Shinji Yuasa, Yoshishige Suzuki, Yoshinori Nagamine
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Publication number: 20090224342Abstract: 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: ApplicationFiled: October 9, 2008Publication date: September 10, 2009Inventors: 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: 7514160Abstract: By varying only the thickness of a known material having superior magnetic characteristics to increase spin polarization without changing the chemical composition, a tunnel magnetoresistive element capable of producing a larger magnetoresistive effect is provided. The tunnel magnetoresistive element includes an underlayer (nonmagnetic or antiferromagnetic metal film); an ultrathin ferromagnetic layer disposed on the underlayer; an insulating layer disposed on the ultrathin ferromagnetic layer; and a ferromagnetic electrode disposed on the insulating layer.Type: GrantFiled: February 12, 2007Date of Patent: April 7, 2009Assignees: National Institute of Advanced Industrial Science and Technology, Japan Science and Technology AgencyInventors: Taro Nagahama, Shinji Yuasa, Yoshishige Suzuki
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Publication number: 20080180862Abstract: 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: March 28, 2008Publication date: July 31, 2008Applicants: 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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Publication number: 20080150643Abstract: Microwave generating and detection portions of a electronic circuit is improved in efficiency and reduced in size. A microwave generating element A comprises a lower electrode 1, a layer 3 formed on the lower electrode 1 in an island shape, forming a magnetoresistance element, an insulator 7 formed on the lower electrode 1 in such a manner as to surround the layer 3 forming the magnetoresistance element, and an upper electrode 5 formed on the insulator 7 and the layer 3 forming the magnetoresistance element. The layer 3 forming the magnetoresistance element includes, in order from the side of the lower electrode 1, a magnetization fixed layer 3a, an intermediate layer 3b, and a magnetization free layer 3c. The magnetization free layer 3c, which is required to produce resonance oscillation based on a current, preferably is dimensioned to be equal to or smaller than 200 nm square in a cross-sectional area and on the order of 1 to 5 nm in film thickness, for example.Type: ApplicationFiled: March 17, 2006Publication date: June 26, 2008Inventors: Yoshishige Suzuki, Shinji Yuasa, Akio Fukushima, Ashwin Tulapurkar
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Publication number: 20080124454Abstract: 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: January 3, 2008Publication date: May 29, 2008Applicants: 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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Publication number: 20080055793Abstract: 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: October 23, 2007Publication date: March 6, 2008Applicants: ANELVA CORPORATION, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: David Djayaprawira, Koji Tsunekawa, Motonobu Nagai, Hiroki Maehara, Shinji Yamagata, Naoki Watanabe, Shinji Yuasa
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Publication number: 20080026253Abstract: Provided are a CCP (current confined path)-CPP (current-perpendicular-to-plane) type giant magneto-resistance (GMR) element having a giant magneto-resistance ratio in a low resistance region (a region of not more than 1 ohm per square micrometer) and a magnetic sensor using this GMR element. The CCP-CPP type GMR element A has a laminated structure of an anti-ferromagnetic layer, a magnetization pinned layer, an intermediate layer and a magnetization free layer, and is formed to have a construction in which a current flows perpendicularly to a film plane. By using an ultrathin magnesium oxide layer having micropores that is preferentially oriented in the (001) direction as the intermediate layer, the magneto-resistance ratio is enhanced, because a current flowing from the magnetization free layer to the magnetization pinned layer (or in the opposite direction) is confined by the metal in the micropores.Type: ApplicationFiled: March 20, 2007Publication date: January 31, 2008Applicant: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: Shinji Yuasa, Akio Fukushima