Patents by Inventor Michihiko Yamanouchi
Michihiko Yamanouchi 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).
-
Patent number: 10706996Abstract: A magnetic material includes a structure in which a first magnetic layer 1 and a second magnetic layer 2 are stacked such that each layer is formed at least partially in a stacking direction by substantially one atomic layer. The first magnetic layer contains Co as a principal component. The second magnetic layer includes at least Ni. The magnetic material has magnetic anisotropy in the stacking direction. Preferably, an atomic arrangement within a film surface of the first magnetic layer and the second magnetic layer has six-fold symmetry.Type: GrantFiled: November 11, 2013Date of Patent: July 7, 2020Assignee: TOHOKU UNIVERSITYInventors: Shunsuke Fukami, Hideo Sato, Michihiko Yamanouchi, Shoji Ikeda, Hideo Ohno
-
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
-
Patent number: 10020039Abstract: A magnetoresistive device includes a magnetic free layer having first and second surfaces, the magnetic free layer being comprised of a ferromagnetic material having a perpendicular magnetic anisotropy, a spin current generation layer contacting the first surface of the magnetic free layer, a tunnel barrier layer having one surface contacting the second surface of the magnetic free layer, a reference layer contacting another surface of the tunnel barrier layer, and a leakage field generation layer including first and second leakage field generation layers each of which is comprised of a ferromagnetic material and generates a leakage field, an in-plane component of the leakage field at an part of the magnetic free layer is formed generating a domain wall having an in-plane magnetization component in the magnetic free layer.Type: GrantFiled: May 2, 2016Date of Patent: July 10, 2018Assignee: TOHOKU UNIVERSITYInventors: Shunsuke Fukami, Michihiko Yamanouchi, Hideo Ohno
-
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
-
Patent number: 9577182Abstract: A magnetoresistance effect element and a magnetic memory having thermal stability expressed by a thermal stability factor of 70 or more even with a fine junction size. The magnetoresistance effect element includes a first magnetic layer of an invariable magnetization direction forming a reference layer, a second magnetic layer of a variable magnetization direction forming a recording layer, and a first non-magnetic layer disposed between the first and second magnetic layers in a thickness direction of the first and second magnetic layers. At least one of the first and second magnetic layers has the following relationship between D (nm) and t (nm): D<0.9t+13, where D is a junction size corresponding to the length of a longest straight line on an end surface perpendicular to the thickness direction, and t is a layer thickness. The junction size is 30 nm or less.Type: GrantFiled: October 20, 2014Date of Patent: February 21, 2017Assignee: TOHOKU UNIVERSITYInventors: Shoji Ikeda, Hideo Sato, Shunsuke Fukami, Michihiko Yamanouchi, Fumihiro Matsukura, Hideo Ohno, Shinya Ishikawa
-
Publication number: 20160329086Abstract: 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: ApplicationFiled: November 13, 2014Publication date: November 10, 2016Applicant: Tohoku UniversityInventors: Shun KANAI, Fumihiro MATSUKURA, Hideo OHNO, Michihiko YAMANOUCHI, Shoji IKEDA, Hideo SATO
-
Publication number: 20160247550Abstract: A magnetoresistive device includes a magnetic free layer having first and second surfaces, the magnetic free layer being comprised of a ferromagnetic material having a perpendicular magnetic anisotropy, a spin current generation layer contacting the first surface of the magnetic free layer, a tunnel barrier layer having one surface contacting the second surface of the magnetic free layer, a reference layer contacting another surface of the tunnel barrier layer, and a leakage field generation layer including first and second leakage field generation layers each of which is comprised of a ferromagnetic material and generates a leakage field, an in-plane component of the leakage field at an part of the magnetic free layer is formed generating a domain wall having an in-plane magnetization component in the magnetic free layer.Type: ApplicationFiled: May 2, 2016Publication date: August 25, 2016Applicants: NEC CORPORATION, TOHOKU UNIVERSITYInventors: Shunsuke FUKAMI, Michihiko YAMANOUCHI, Hideo OHNO
-
Publication number: 20160233416Abstract: A magnetoresistance effect element and a magnetic memory having thermal stability expressed by a thermal stability factor of 70 or more even with a fine junction size. The magnetoresistance effect element includes a first magnetic layer of an invariable magnetization direction forming a reference layer, a second magnetic layer of a variable magnetization direction forming a recording layer, and a first non-magnetic layer disposed between the first and second magnetic layers in a thickness direction of the first and second magnetic layers. At least one of the first and second magnetic layers has the following relationship between D (nm) and t (nm): D<0.9t+13, where D is a junction size corresponding to the length of a longest straight line on an end surface perpendicular to the thickness direction, and t is a layer thickness. The junction size is 30 nm or less.Type: ApplicationFiled: October 20, 2014Publication date: August 11, 2016Applicant: TOHOKU UNIVERSITYInventors: Shoji IKEDA, Hideo SATO, Shunsuke FUKAMI, Michihiko YAMANOUCHI, Fumihiro MATSUKURA, Hideo OHNO, Shinya ISHIKAWA
-
Patent number: 9202545Abstract: A magnetoresistance effect element including a recording layer of high thermal stability to perform perpendicular magnetic recording within a film surface, and a magnetic memory using the element. The element includes: a first ferromagnetic layer of an invariable magnetization direction; a second ferromagnetic layer of a variable magnetization direction; a first non-magnetic layer between the first and second ferromagnetic layers; current supply terminals connected to the first and second ferromagnetic layers; a non-magnetic coupling layer on a surface of the second ferromagnetic layer opposite the first non-magnetic layer; a third ferromagnetic layer of a variable magnetization direction on a surface of the non-magnetic coupling layer opposite the second ferromagnetic layer; and a second non-magnetic layer on a surface of the third ferromagnetic layer opposite the non-magnetic coupling layer.Type: GrantFiled: March 25, 2013Date of Patent: December 1, 2015Assignee: TOHOKU UNIVERSITYInventors: Hideo Sato, Shunsuke Fukami, Michihiko Yamanouchi, Shoji Ikeda, Fumihiro Matsukura, Hideo Ohno
-
Publication number: 20150332818Abstract: A magnetic material includes a structure in which a first magnetic layer 1 and a second magnetic layer 2 are stacked such that each layer is formed at least partially in a stacking direction by substantially one atomic layer. The first magnetic layer contains Co as a principal component. The second magnetic layer includes at least Ni. The magnetic material has magnetic anisotropy in the stacking direction. Preferably, an atomic arrangement within a film surface of the first magnetic layer and the second magnetic layer has six-fold symmetry.Type: ApplicationFiled: November 11, 2013Publication date: November 19, 2015Inventors: Shunsuke FUKAMI, Hideo SATO, Michihiko YAMANOUCHI, Shoji IKEDA, Hideo OHNO
-
Patent number: 9070457Abstract: 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: GrantFiled: May 24, 2012Date of Patent: June 30, 2015Assignee: Tohoku UniversityInventors: Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi, Hideo Sato, Katsuya Miura
-
Publication number: 20150109853Abstract: A magnetoresistance effect element including a recording layer of high thermal stability to perform perpendicular magnetic recording within a film surface, and a magnetic memory using the element. The element includes: a first ferromagnetic layer of an invariable magnetization direction; a second ferromagnetic layer of a variable magnetization direction; a first non-magnetic layer between the first and second ferromagnetic layers; current supply terminals connected to the first and second ferromagnetic layers; a non-magnetic coupling layer on a surface of the second ferromagnetic layer opposite the first non-magnetic layer; a third ferromagnetic layer of a variable magnetization direction on a surface of the non-magnetic coupling layer opposite the second ferromagnetic layer; and a second non-magnetic layer on a surface of the third ferromagnetic layer opposite the non-magnetic coupling layer.Type: ApplicationFiled: March 25, 2013Publication date: April 23, 2015Applicant: TOHOKU UNIVERSITYInventors: Hideo Sato, Shunsuke Fukami, Michihiko Yamanouchi, Shoji Ikeda, Fumihiro Matsukura, Hideo Ohno
-
Publication number: 20140097509Abstract: 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: ApplicationFiled: April 19, 2012Publication date: April 10, 2014Applicant: TOHOKU UNIVERSITYInventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi
-
Patent number: 8331140Abstract: 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: GrantFiled: January 14, 2005Date of Patent: December 11, 2012Assignees: Japan Science and Technology Agency, Tohoku UniversityInventors: Hideo Ohno, Fumihiro Matsukura, Daichi Chiba, Michihiko Yamanouchi
-
Publication number: 20120300543Abstract: 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: ApplicationFiled: May 24, 2012Publication date: November 29, 2012Inventors: Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi, Hideo Sato, Katsuya Miura
-
Publication number: 20080137405Abstract: 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: ApplicationFiled: January 14, 2005Publication date: June 12, 2008Applicants: JAPAN SCIENCE AND TECHNOLOGY AGENCY, Tohoku UniversityInventors: Hideo Ohno, Fumihiro Matsukura, Daichi Chiba, Michihiko Yamanouchi