Patents by Inventor Shoji Ikeda
Shoji Ikeda 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: 10586580Abstract: A magnetic tunnel junction element with a high tunnel magnetic resistance ratio can prevent a recording layer from being damaged. A reference layer includes a ferromagnetic body, and has magnetization direction fixed in the vertical direction. A barrier layer includes non-magnetic body, and disposed on one surface side of the reference layer. A recording layer is disposed to sandwich barrier layer between itself and reference layer. The recording layer includes a first ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in a vertical direction; a first non-magnetic layer including at least one of Mg, MgO, C, Li, Al, and Si, second non-magnetic layer including at least one of Ta, Hf, W, Mo, Nb, Zr, Y, Sc, Ti, V, and Cr, and second ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in a vertical direction.Type: GrantFiled: May 19, 2017Date of Patent: March 10, 2020Assignee: TOHOKU UNIVERSITYInventors: Hiroaki Honjo, Shoji Ikeda, Hideo Sato, Tetsuo Endoh, Hideo Ohno
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Publication number: 20200044142Abstract: The present invention provides a magnetoresistance effect element which has a high thermal stability factor ? and in which a magnetization direction of a recording layer is a perpendicular direction with respect to a film surface, and a magnetic memory including the same. Magnetic layers of a recording layer of the magnetoresistance effect element are divided into at least two, and an Fe composition with respect to a sum total of atomic fractions of magnetic elements in each magnetic layer is changed before stacking the magnetic layers.Type: ApplicationFiled: January 18, 2017Publication date: February 6, 2020Inventors: Hiroaki HONJO, Tetsuo ENDOH, Shoji IKEDA, Hideo SATO, Hideo OHNO
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Publication number: 20190363245Abstract: A structure used in the formation of a spintronics element, the spintronics element to include a plurality of laminated layers, includes a substrate, a plurality of laminated layers formed on the substrate, an uppermost layer of the plurality of laminated layers being a non-magnetic layer containing oxygen, and a protection layer directly formed on the uppermost layer, the protection layer preventing alteration of characteristics of the uppermost layer while exposed in an atmosphere including H2O, a partial pressure of H2O in the atmosphere being equal to or larger than 10?4 Pa, no other layer being directly formed on the protection layer.Type: ApplicationFiled: July 16, 2019Publication date: November 28, 2019Applicant: TOHOKU UNIVERSITYInventors: Soshi SATO, Masaaki NIWA, Hiroaki HONJO, Shoji IKEDA, Hideo OHNO, Tetsuo ENDO
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Publication number: 20190304526Abstract: A magnetic tunnel junction element with a high MR ratio, and can prevent a recording layer from being damaged, and magnetic memory. A reference layer includes a ferromagnetic body, and has magnetization direction fixed in the vertical direction. A barrier layer includes non-magnetic body, and disposed on one surface side of the reference layer. A recording layer is disposed to sandwich barrier layer between itself and reference layer. The recording layer includes a first ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in vertical direction; a first non-magnetic layer including at least one of Mg, MgO, C, Li, Al, and Si, second non-magnetic layer including at least one of Ta, Hf, W, Mo, Nb, Zr, Y, Sc, Ti, V, and Cr, and second ferromagnetic layer including at least one of Co and Fe, and having a magnetization direction variable in vertical direction.Type: ApplicationFiled: May 19, 2017Publication date: October 3, 2019Applicant: TOHOKU UNIVERSITYInventors: Hiroaki HONJO, Shoji IKEDA, Hideo SATO, Tetsuo ENDOH, Hideo OHNO
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Publication number: 20190304741Abstract: An evaluation method for an electronic device provided with an insulating film between a pair of electrode layers includes preparing a sample that has a tunnel barrier insulating film as the insulating film; irradiating the sample with electron beams from a plurality of angles to acquire a plurality of images; and performing image processing using the plurality of images to reconstruct a stereoscopic image and generate a cross-sectional image of the sample from the stereoscopic image.Type: ApplicationFiled: March 21, 2019Publication date: October 3, 2019Inventors: Masaaki Niwa, Tetsuo Endoh, Shoji Ikeda, Kosuke Kimura
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Patent number: 10424725Abstract: A spintronics element including a ferromagnetic layer containing boron, and a diffusion stopper film covering a side face of the ferromagnetic layer partially or entirely, the side face in direct contact with diffusion stopper film, so as to prevent out-diffusion of the boron contained in the ferromagnetic layer. The diffusion stopper film contains boron at a concentration higher than a concentration of the boron in a portion of the ferromagnetic layer where the ferromagnetic layer contacts the diffusion stopper film.Type: GrantFiled: June 20, 2018Date of Patent: September 24, 2019Assignee: TOHOKU UNIVERSITYInventors: Soshi Sato, Masaaki Niwa, Hiroaki Honjo, Shoji Ikeda, Hideo Sato, Hideo Ohno, Tetsuo Endoh
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Patent number: 10396274Abstract: A method of manufacturing a spintronics element from laminated layers. The method includes (a) forming a plurality of laminated layers in manufacturing equipment, (b) forming a wafer in the manufacturing equipment, including applying a protection layer directly on a non-magnetic uppermost layer of the laminated layers so that the protection layer prevents alteration of characteristics of the uppermost layer, and (c) exposing the wafer, outside of the manufacturing equipment, to an atmosphere that includes H2O having a partial pressure in the atmosphere equal to or larger than 10?4 Pa.Type: GrantFiled: March 8, 2016Date of Patent: August 27, 2019Assignee: TOHOKU UNIVERSITYInventors: Soshi Sato, Masaaki Niwa, Hiroaki Honjo, Shoji Ikeda, Hideo Ohno, Tetsuo Endo
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Publication number: 20190229262Abstract: A magnetic tunnel junction element configured by stacking, in a following stack order, a fixed layer formed of a ferromagnetic body and in which a magnetization direction is fixed, a magnetic coupling layer formed of a nonmagnetic body, a reference layer formed of a ferromagnetic body and in which the magnetization direction is fixed, a barrier layer formed of a nonmagnetic body, and a recording layer formed of a ferromagnetic body, a barrier layer formed of a nonmagnetic body, and a recording layer formed by sandwiching an insertion layer formed of a nonmagnetic body between first and second ferromagnetic layers, wherein the magnetic coupling layer is formed using a sputtering gas in which a value of a ratio in which a mass number of an element used in the magnetic coupling layer divided by the mass number of the sputtering gas itself is 2.2 or smaller.Type: ApplicationFiled: March 17, 2017Publication date: July 25, 2019Applicant: TOHOKU UNIVERSITYInventors: Hiroaki Honjo, Shoji Ikeda, Hideo Sato, Tetsuo Endoh, Hideo Ohno
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Publication number: 20190198755Abstract: A method for producing a magnetic memory includes: forming a magnetic film having a non-magnetic layer between a first magnetic layer and a second magnetic layer on a substrate having an electrode layer; performing annealing treatment at a first treatment temperature in a state where a magnetic field is applied in a direction perpendicular to a film surface of the first or the second magnetic layer in vacuum; forming a magnetic tunnel junction element; forming a protective film protecting the magnetic tunnel junction element; a formation accompanied by thermal history, in which a constituent element of a magnetic memory is formed after the protective film formation on the substrate; and implementing annealing treatment at a second treatment temperature lower than the first treatment temperature on the substrate in an annealing treatment chamber, in vacuum or inert gas wherein no magnetic field is applied.Type: ApplicationFiled: August 28, 2017Publication date: June 27, 2019Inventors: Kenchi ITO, Tetsuo ENDOH, Shoji IKEDA, Hideo SATO, Hideo OHNO, Sadahiko MIURA, Masaaki NIWA, Hiroaki HONJO
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Publication number: 20190189917Abstract: A magnetic tunnel junction element includes, in a following stack order, an underlayer formed of a metal material, a fixed layer formed of a ferromagnetic body, a magnetic coupling layer formed of a nonmagnetic body, a reference layer formed of a ferromagnetic body, a barrier layer formed of a nonmagnetic body, and a recording layer formed of a ferromagnetic body, or alternatively, the magnetic tunnel junction element includes, in a following stack order, a recording layer formed of a ferromagnetic body, a barrier layer formed of a nonmagnetic body, a reference layer formed of a ferromagnetic body, a magnetic coupling layer formed of a nonmagnetic body, an underlayer formed of a metal material, and a fixed layer formed of a ferromagnetic body, wherein the fixed layer is formed and stacked after performing plasma treatment to a surface of the underlayer having been formed.Type: ApplicationFiled: March 21, 2017Publication date: June 20, 2019Applicant: TOHOKU UNIVERSITYInventors: Hiroaki Honjo, Tetsuo Endoh, Shoji Ikeda, Hideo Sato, Hideo Ohno
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Patent number: 10263180Abstract: A magnetoresistance effect element includes a reference layer made of a ferromagnetic material, a recording layer made of a ferromagnetic material, and a barrier layer disposed between the reference layer and the recording layer. The reference layer and the recording layer have an in-plane magnetization direction parallel to a surface of the layers. The recording layer has a shape that has short axis and long axis perpendicular to the short axis in plan view. A first value obtained by dividing a thickness of the recording layer by a length of the short axis of the recording layer is greater than 0.3 and smaller than 1.Type: GrantFiled: July 22, 2017Date of Patent: April 16, 2019Assignee: TOHOKU UNIVERSITYInventors: Hideo Sato, Shinya Ishikawa, Shunsuke Fukami, Shoji Ikeda, Fumihiro Matsukura, Hideo Ohno, Tetsuo Endoh
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Publication number: 20190074433Abstract: A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface of the layers. An atomic fraction of all magnetic elements to all magnetic and non-magnetic elements included in the second magnetic layer is smaller than that of the first magnetic layer.Type: ApplicationFiled: November 2, 2018Publication date: March 7, 2019Applicant: TOHOKU UNIVERSITYInventors: Hideo SATO, Shoji IKEDA, Mathias BERSWEILER, Hiroaki HONJO, Kyota WATANABE, Shunsuke FUKAMI, Fumihiro MATSUKURA, Kenchi ITO, Masaaki NIWA, Tetsuo ENDOH, Hideo OHNO
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Publication number: 20190019944Abstract: A magnetic tunnel junction element (10) includes a configuration in which a reference layer (14) that includes a ferromagnetic material, a barrier layer (15) that includes O, a recording layer (16) that includes a ferromagnetic material including Co or Fe, a first protective layer (17) that includes O, and a second protective layer (18) that includes at least one of Pt, Ru, Co, Fe, CoB, FeB, or CoFeB are layered.Type: ApplicationFiled: November 18, 2016Publication date: January 17, 2019Inventors: Hideo Sato, Yoshihisa Horikawa, Shunsuke Fukami, Shoji Ikeda, Fumihiro Matsukura, Hideo Ohno, Tetsuo Endoh, Hiroaki Honjo
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Patent number: 10164174Abstract: A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface if the layers. The second magnetic layer has a saturation magnetization lower than that of the first magnetic layer, and an interfacial magnetic anisotropy energy density (Ki) at the interface between the first magnetic layer and the first non-magnetic layer is greater than that of an interface between the first non-magnetic layer and second magnetic layers if being disposed adjacent each other.Type: GrantFiled: January 16, 2018Date of Patent: December 25, 2018Assignee: TOHOKU UNIVERSITYInventors: Hideo Sato, Shoji Ikeda, Mathias Bersweiler, Hiroaki Honjo, Kyota Watanabe, Shunsuke Fukami, Fumihiro Matsukura, Kenchi Ito, Masaaki Niwa, Tetsuo Endoh, Hideo Ohno
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Patent number: 10127957Abstract: A control method for a magnetoresistance effect element and a control device for the magnetoresistance effect element that provide a higher writing speed and lower power consumption. When the magnetization direction of a second magnetic layer is nearly parallel to the magnetization direction of a first magnetic layer, a first voltage is applied across the first and second magnetic layer so that the magnetization direction of the second magnetic layer is reversed by modifying the direction of the magnetization easy axis thereof, followed by the application of a second voltage. When the magnetization direction of the second magnetic layer is nearly antiparallel to the magnetization direction of the first magnetic layer, a third voltage is applied across the first magnetic layer and the second magnetic layer, followed by the application of a fourth voltage so that current flows from the second magnetic layer toward the first magnetic layer.Type: GrantFiled: November 13, 2014Date of Patent: November 13, 2018Assignee: TOHOKU UNIVERSITYInventors: Shun Kanai, Fumihiro Matsukura, Hideo Ohno, Michihiko Yamanouchi, Shoji Ikeda, Hideo Sato
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Publication number: 20180301621Abstract: A spintronics element including a ferromagnetic layer containing boron, and a diffusion stopper film covering a side face of the ferromagnetic layer partially or entirely, the side face in direct contact with diffusion stopper film, so as to prevent out-diffusion of the boron contained in the ferromagnetic layer. The diffusion stopper film contains boron at a concentration higher than a concentration of the boron in a portion of the ferromagnetic layer where the ferromagnetic layer contacts the diffusion stopper film.Type: ApplicationFiled: June 20, 2018Publication date: October 18, 2018Applicant: TOHOKU UNIVERSITYInventors: Soshi SATO, Masaaki NIWA, Hiroaki HONJO, Shoji IKEDA, Hideo SATO, Hideo OHNO, Tetsuo ENDOH
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Publication number: 20180175286Abstract: A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface if the layers. The second magnetic layer has a saturation magnetization lower than that of the first magnetic layer, and an interfacial magnetic anisotropy energy density (Ki) at the interface between the first magnetic layer and the first non-magnetic layer is greater than that of an interface between the first non-magnetic layer and second magnetic layers if being disposed adjacent each other.Type: ApplicationFiled: January 16, 2018Publication date: June 21, 2018Applicant: TOHOKU UNIVERSITYInventors: Hideo SATO, Shoji IKEDA, Mathias BERSWEILER, Hiroaki HONJO, Kyota WATANABE, Shunsuke FUKAMI, Fumihiro MATSUKURA, Kenchi ITO, Masaaki NIWA, Tetsuo ENDOH, Hideo OHNO
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Publication number: 20170324030Abstract: A magnetoresistance effect element includes a reference layer made of a ferromagnetic material, a recording layer made of a ferromagnetic material, and a barrier layer disposed between the reference layer and the recording layer. The reference layer and the recording layer have an in-plane magnetization direction parallel to a surface of the layers. The recording layer has a shape that has short axis and long axis perpendicular to the short axis in plan view. A first value obtained by dividing a thickness of the recording layer by a length of the short axis of the recording layer is greater than 0.3 and smaller than 1.Type: ApplicationFiled: July 22, 2017Publication date: November 9, 2017Applicant: TOHOKU UNIVERSITYInventors: Hideo SATO, Shinya ISHIKAWA, Shunsuke FUKAMI, Shoji IKEDA, Fumihiro MATSUKURA, Hideo OHNO, Tetsuo ENDOH
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Patent number: 9799822Abstract: 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: GrantFiled: April 19, 2012Date of Patent: October 24, 2017Assignees: NEC CORPORATION, TOHOKU UNIVERSITYInventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi
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Publication number: 20170263854Abstract: A method of manufacturing a spintronics element from laminated layers. The method includes (a) forming a plurality of laminated layers in manufacturing equipment, (b) forming a wafer in the manufacturing equipment, including applying a protection layer directly on a non-magnetic uppermost layer of the laminated layers so that the protection layer prevents alteration of characteristics of the uppermost layer, and (c) exposing the wafer, outside of the manufacturing equipment, to an atmosphere that includes H2O having a partial pressure in the atmosphere equal to or larger than 10?4 Pa.Type: ApplicationFiled: March 8, 2016Publication date: September 14, 2017Applicant: TOHOKU UNIVERSITYInventors: Soshi SATO, Masaaki NIWA, Hiroaki HONJO, Shoji IKEDA, Hideo OHNO, Tetsuo ENDO