Patents by Inventor Tohru Oikawa
Tohru Oikawa 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: 20180123028Abstract: A spin-orbit torque magnetization rotational element includes: a ferromagnetic metal layer, a magnetization direction of which is configured to be changed; a spin-orbit torque wiring bonded to the ferromagnetic metal layer; and an interfacial distortion supply layer bonded to a surface of the spin-orbit torque wiring on a side opposite to the ferromagnetic metal layer.Type: ApplicationFiled: October 25, 2017Publication date: May 3, 2018Applicant: TDK CORPORATIONInventors: Yohei SHIOKAWA, Tomoyuki SASAKI, Tohru OIKAWA
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Publication number: 20180033953Abstract: This spin current magnetization reversal element includes a magnetoresistance effect element having a first ferromagnetic metal layer having a fixed magnetization direction, a second ferromagnetic metal layer having a variable magnetization direction, and a non-magnetic layer sandwiched between the first ferromagnetic metal layer and the second ferromagnetic metal layer, and spin-orbit torque wiring which extends in a first direction that intersects the stacking direction of the magnetoresistance effect element, and contacts the surface of the magnetoresistance effect element on the side facing the second ferromagnetic metal layer, wherein at least one surface of the second ferromagnetic metal layer in the stacking direction has an inclined surface that is inclined in the first direction, and the direction of magnetization of the second ferromagnetic metal layer is inclined due to the inclined surface.Type: ApplicationFiled: July 5, 2017Publication date: February 1, 2018Applicant: TDK CORPORATIONInventors: Tomoyuki SASAKI, Tatsuo SHIBATA, Tohru OIKAWA
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Patent number: 9825155Abstract: The magnetoresistive element includes a semiconductor channel layer, a pinned layer disposed on the semiconductor channel layer via a first tunnel layer, a free layer disposed on the semiconductor channel layer via a second tunnel layer, wherein the semiconductor channel layer includes a first region containing an interface with the first tunnel layer, a second region containing an interface with the second tunnel layer, and a third region, impurity concentrations in the first and second regions are higher than 1×1019 cm?3, an impurity concentration in the third region is 1×1019 cm?3 or less, the first and second regions are separated by the third region, and the impurity concentrations in the first and second regions decrease in the thickness direction of the semiconductor channel layer from the interface between the semiconductor channel layer and the first tunnel layer and the interface between the semiconductor channel layer and the second tunnel layer.Type: GrantFiled: November 19, 2014Date of Patent: November 21, 2017Assignee: TDK CORPORATIONInventors: Tomoyuki Sasaki, Tohru Oikawa
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Patent number: 9728713Abstract: Spin-transport elements using semiconductors have had the problem of higher element resistance than conventional GMR elements and TMR elements, making it difficult to obtain high magnetoresistance ratios. A magnetoresistive element including a semiconductor channel layer; a first ferromagnetic layer disposed on the semiconductor channel layer; a second ferromagnetic layer disposed away from the first ferromagnetic layer; and a non-magnetic first reference electrode disposed away from the first ferromagnetic layer and the second ferromagnetic layer, wherein current is input from the second ferromagnetic layer to the first ferromagnetic layer through the semiconductor channel layer, a voltage between the second ferromagnetic layer and the first reference electrode is output.Type: GrantFiled: November 14, 2014Date of Patent: August 8, 2017Assignee: TDK CORPORATIONInventors: Tomoyuki Sasaki, Tohru Oikawa, Hayato Koike
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Publication number: 20160293740Abstract: The magnetoresistive element includes a semiconductor channel layer, a pinned layer disposed on the semiconductor channel layer via a first tunnel layer, a free layer disposed on the semiconductor channel layer via a second tunnel layer, wherein the semiconductor channel layer includes a first region containing an interface with the first tunnel layer, a second region containing an interface with the second tunnel layer, and a third region, impurity concentrations in the first and second regions are higher than 1×1019 cm?3, an impurity concentration in the third region is 1×1019 cm?3 or less, the first and second regions are separated by the third region, and the impurity concentrations in the first and second regions decrease in the thickness direction of the semiconductor channel layer from the interface between the semiconductor channel layer and the first tunnel layer and the interface between the semiconductor channel layer and the second tunnel layer.Type: ApplicationFiled: November 19, 2014Publication date: October 6, 2016Applicant: TDK CORPORATIONInventors: Tomoyuki SASAKI, Tohru OIKAWA
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Publication number: 20160284982Abstract: Spin-transport elements using semiconductors have had the problem of higher element resistance than conventional GMR elements and TMR elements, making it difficult to obtain high magnetoresistance ratios. A magnetoresistive element including a semiconductor channel layer; a first ferromagnetic layer disposed on the semiconductor channel layer; a second ferromagnetic layer disposed away from the first ferromagnetic layer; and a non-magnetic first reference electrode disposed away from the first ferromagnetic layer and the second ferromagnetic layer, wherein current is input from the second ferromagnetic layer to the first ferromagnetic layer through the semiconductor channel layer, a voltage between the second ferromagnetic layer and the first reference electrode is output.Type: ApplicationFiled: November 14, 2014Publication date: September 29, 2016Applicant: TDK CorporationInventors: Tomoyuki SASAKI, Tohru OIKAWA, Hayato KOIKE
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Patent number: 9401419Abstract: A spin transport device includes a semiconductor layer 3, a first ferromagnetic layer 1 provided on the semiconductor layer 3 via a first tunnel barrier layer 5A, and a second ferromagnetic layer 2 provided on the semiconductor layer 3 via a second tunnel barrier layer 5B to be spaced from the first ferromagnetic layer 1, and the semiconductor layer 3 includes a first region RI broadening in a direction away from the first ferromagnetic layer 1 along a direction orthogonal to a thickness direction from the first ferromagnetic layer 1, and a second region R12 extending in a direction toward the second ferromagnetic layer 2 along the direction orthogonal to the thickness direction from the first ferromagnetic layer 1. The second region R12 has a relatively higher impurity concentration than the first region R1.Type: GrantFiled: April 12, 2012Date of Patent: July 26, 2016Assignee: TDK CORPORATIONInventors: Tomoyuki Sasaki, Tohru Oikawa
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Patent number: 9348004Abstract: A magnetic sensor includes a channel layer, a magnetization free layer placed on a first section of the channel layer, and a magnetization-fixed layer placed on a second section of the channel layer. A thickness of the channel layer of the first section is different from a thickness of the channel layer of the second section and a resistance of an interface between the channel layer and the magnetization free layer is lower than a resistance of an interface between the channel layer and the magnetization-fixed layer.Type: GrantFiled: July 25, 2014Date of Patent: May 24, 2016Assignee: TDK CORPORATIONInventors: Tomoyuki Sasaki, Tohru Oikawa
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Patent number: 9110124Abstract: A magnetic sensor is provided with a channel of a semiconductor, a first insulating film and a metal body arranged opposite to each other with the channel in between, a ferromagnet provided on the first insulating film, a first reference electrode connected to the metal body, a second reference electrode connected to the metal body, a magnetic shield covering a portion opposed to the ferromagnet in the channel, and a second insulating film provided between the channel and the magnetic shield. The magnetic shield has a through hole extending toward the portion opposed to the ferromagnet in the channel.Type: GrantFiled: July 1, 2011Date of Patent: August 18, 2015Assignee: TDK CORPORATIONInventors: Tomoyuki Sasaki, Tohru Oikawa
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Publication number: 20150035524Abstract: A magnetic sensor includes a channel layer, a magnetization free layer placed on a first section of the channel layer, and a magnetization-fixed layer placed on a second section of the channel layer. A thickness of the channel layer of the first section is different from a thickness of the channel layer of the second section and a resistance of an interface between the channel layer and the magnetization free layer is lower than a resistance of an interface between the channel layer and the magnetization-fixed layer.Type: ApplicationFiled: July 25, 2014Publication date: February 5, 2015Inventors: Tomoyuki SASAKI, Tohru OIKAWA
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Publication number: 20150001601Abstract: To provide a spin injection electrode structure capable of injecting spins into a semiconductor with high efficiency and a spin transport element having the same. Aluminum oxide containing a ?-phase is used as a material making up a tunnel barrier layer. A protective film is formed outside the tunnel barrier layer. This allows a good spin injection electrode structure with few defects in a crystal or at a junction interface to be obtained, enables spins to be injected into a semiconductor with high efficiency, and allows a spin transport element having high output characteristics at room temperature to be provided.Type: ApplicationFiled: February 12, 2013Publication date: January 1, 2015Inventors: Hayato Koike, Tohru Oikawa, Tomoyuki Sasaki
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Patent number: 8872514Abstract: A magnetic sensor comprises a first ferromagnetic body, a second ferromagnetic body, a channel extending from the first ferromagnetic body to the second ferromagnetic body, a magnetic shield covering the channel, and an insulating film disposed between the channel and the magnetic shield, while the magnetic shield has a through-hole extending toward the channel.Type: GrantFiled: January 31, 2011Date of Patent: October 28, 2014Assignee: TDK CorporationInventors: Tomoyuki Sasaki, Tohru Oikawa, Kiyoshi Noguchi
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Patent number: 8861136Abstract: A spin conduction element includes a main channel layer having a first electrode, a second electrode, a third electrode, a fourth electrode, a fifth electrode, and a sixth electrode, and extending in a first direction. Spins are injected into the main channel layer from a second ferromagnetic layer constituting the second electrode and a fourth ferromagnetic layer constituting the fourth electrode, and a spin current is detected as a voltage in a third ferromagnetic layer constituting the third electrode.Type: GrantFiled: March 13, 2013Date of Patent: October 14, 2014Assignee: TDK CorporationInventors: Tomoyuki Sasaki, Tohru Oikawa, Hayato Koike
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Publication number: 20130258524Abstract: A spin conduction element includes a main channel layer having a first electrode, a second electrode, a third electrode, a fourth electrode, a fifth electrode, and a sixth electrode, and extending in a first direction. Spins are injected into the main channel layer from a second ferromagnetic layer constituting the second electrode and a fourth ferromagnetic layer constituting the fourth electrode, and a spin current is detected as a voltage in a third ferromagnetic layer constituting the third electrode.Type: ApplicationFiled: March 13, 2013Publication date: October 3, 2013Applicant: TDK CORPORATIONInventors: Tomoyuki SASAKI, Tohru OIKAWA, Hayato KOIKE
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Patent number: 8502332Abstract: A magnetic sensor 1 comprises a main channel layer 7a having first, second, and third regions 71, 72, 73 and extending in a first direction; a first ferromagnetic layer 12A mounted on the first region 71; a second ferromagnetic layer 12B mounted on the second region 72; a projection channel layer 7b projecting in a direction perpendicular to a thickness direction of the main channel layer 7a from a side face of the third region 73 between the first and second regions 71, 72 in the main channel layer 7a; and a magnetic shield S covering both sides in the thickness direction of the projection channel layer 7b and both sides in the first direction of the projection channel layer 7b and exposing an end face 7c in the projecting direction of the projection channel layer 7b.Type: GrantFiled: September 7, 2011Date of Patent: August 6, 2013Assignee: TDK CorporationInventors: Tomoyuki Sasaki, Tohru Oikawa
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Patent number: 8492809Abstract: The present invention provides a spin injection electrode structure, a spin transport element, and a spin transport device which enable effective spin injection in a silicon channel layer at room temperature. A spin injection electrode structure IE comprises a silicon channel layer 12, a first magnesium oxide film 13A disposed on a first part of the silicon channel layer 12, and a first ferromagnetic layer 14A disposed on the first magnesium oxide film 13A. The first magnesium oxide film 13A partly includes a first lattice-matched part P lattice-matched with both of the silicon channel layer 12 and the first ferromagnetic layer 14A.Type: GrantFiled: August 24, 2011Date of Patent: July 23, 2013Assignees: TDK Corporation, Akita PrefectureInventors: Tomoyuki Sasaki, Tohru Oikawa, Kiyoshi Noguchi, Toshio Suzuki
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Patent number: 8488282Abstract: A magnetic sensor comprises a channel, a ferromagnetic body and first and second reference electrodes on the channel, a magnetic shield covering a part of the channel opposing the ferromagnetic body, and an insulating film disposed between the channel and the magnetic shield, while the magnetic shield has a through-hole extending toward the part of the channel opposing the ferromagnetic body.Type: GrantFiled: January 31, 2011Date of Patent: July 16, 2013Assignee: TDK CorporationInventors: Tomoyuki Sasaki, Tohru Oikawa, Kiyoshi Noguchi
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Patent number: 8481337Abstract: An object of the present invention is to provide a silicon spin transport device manufacturing method and silicon spin transport device whereby improved voltage output characteristics can be obtained. The silicon spin transport device manufacturing method comprises: a first step of patterning a silicon film by wet etching and forming a silicon channel layer; and a second step of forming a magnetization free layer and a magnetization fixed layer, which are apart from each other, on the silicon channel layer.Type: GrantFiled: January 20, 2010Date of Patent: July 9, 2013Assignee: TDK CorporationInventors: Tomoyuki Sasaki, Tohru Oikawa, Katsumichi Tagami
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Patent number: 8426929Abstract: The magnetic sensor includes a base substrate having a magnetic shield layer; a single-domain semiconductor crystal layer attached via an insulating film on the magnetic shield layer of the base substrate; a first ferromagnetic layer formed on top of the semiconductor crystal layer on the opposite side of the semiconductor crystal layer to the insulating film, via a first tunnel barrier layer; and a second ferromagnetic layer formed, at a distance from the first ferromagnetic layer, on top of the semiconductor crystal layer on the opposite side of the semiconductor crystal layer to the insulating film, via a second tunnel barrier layer.Type: GrantFiled: February 14, 2012Date of Patent: April 23, 2013Assignee: TDK CorporationInventors: Tomoyuki Sasaki, Tohru Oikawa, Kiyoshi Noguchi
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Patent number: 8324672Abstract: A spin transport device which comprises a channel, first and second insulating layers, a magnetization fixed layer, a magnetization free layer, first and second wirings, and satisfies at least one of following conditions A and B, Condition A: The first wiring includes a vertical portion which extends in a thickness direction of the magnetization fixed layer on the magnetization fixed layer, and a horizontal portion which extends from the vertical portion that is apart from the magnetization fixed layer side in a direction crossing the thickness direction of the magnetization fixed layer, and Condition B: The second wiring includes a vertical portion which extends in a thickness direction of the magnetization free layer on the magnetization free layer, and a horizontal portion which extends from the vertical portion that is apart from the magnetization free layer side in a direction crossing the thickness direction of the magnetization free layer.Type: GrantFiled: June 23, 2010Date of Patent: December 4, 2012Assignee: TDK CorporationInventors: Tomoyuki Sasaki, Tohru Oikawa, Katsumichi Tagami