Patents by Inventor Nobuyuki Ishiwata
Nobuyuki Ishiwata 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: 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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Patent number: 9379312Abstract: A magnetoresistive effect element of the present invention includes: a domain wall motion layer, a spacer layer and a reference layer. The domain wall motion layer is made of ferromagnetic material with perpendicular magnetic anisotropy. The spacer layer is formed on the domain wall motion layer and made of non-magnetic material. The reference layer is formed on the spacer layer and made of ferromagnetic material, magnetization of the reference layer being fixed. The domain wall motion layer includes at least one domain wall, and stores data corresponding to a position of the domain wall. An anisotropy magnetic field of the domain wall motion layer is larger than a value in which the domain wall motion layer can hold the perpendicular magnetic anisotropy, and smaller than an essential value of an anisotropy magnetic field of the ferromagnetic material of the domain wall motion layer.Type: GrantFiled: December 14, 2010Date of Patent: June 28, 2016Assignee: NEC CORPORATIONInventors: Tadahiko Sugibayashi, Eiji Kariyada, Kaoru Mori, Norikazu Ohshima, Shunsuke Fukami, Tetsuhiro Suzuki, Hironobu Tanigawa, Sadahiko Miura, Nobuyuki Ishiwata
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Patent number: 9083336Abstract: A non-volatile logic operation device includes an operation unit that is connected to a first input terminal, a second input terminal, and an output terminal, includes an operation layer, a first non-magnetic layer, and a reference layer, and outputs from the output terminal a result of a logic operation on signals applied at the first input terminal and the second input terminal, and a control unit that is connected to a third input terminal, and includes a control layer. The control unit is arranged in the vicinity of the operation unit.Type: GrantFiled: January 5, 2012Date of Patent: July 14, 2015Assignee: NEC CorporationInventors: Shunsuke Fukami, Nobuyuki Ishiwata
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Patent number: 8994130Abstract: A magnetic memory element includes: a first magnetization free layer formed of a ferromagnetic material having perpendicular magnetic anisotropy; a second magnetization free layer provided near the first magnetization free layer and formed of a ferromagnetic material having in-plane magnetic anisotropy; a reference layer formed of a ferromagnetic material having in-plane magnetic anisotropy; and a non-magnetic layer provided between the second magnetization free layer and the reference layer. The first magnetization free layer includes: a first magnetization fixed region of which magnetization is fixed, a second magnetization fixed region of which magnetization is fixed, and a magnetization free region which is connected to the first magnetization fixed region and the second magnetization fixed region, and of which magnetization can be switched. The second magnetization free layer is included in the first magnetization free layer in a plane parallel to a substrate.Type: GrantFiled: January 28, 2010Date of Patent: March 31, 2015Assignee: NEC CorporationInventors: Shunsuke Fukami, Tetsuhiro Suzuki, Kiyokazu Nagahara, Nobuyuki Ishiwata, Norikazu Ohshima
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Patent number: 8923042Abstract: A magnetic random access memory according to the present invention is provided with: a magnetic recording layer including a magnetization free region having a reversible magnetization, wherein a write current is flown through the magnetic recording layer in an in-plane direction; a magnetization fixed layer having a fixed magnetization; a non-magnetic layer provided between the magnetization free region and the magnetization fixed layer; and a heat sink structure provided to be opposed to the magnetic recording layer and having a function of receiving and radiating heat generated in the magnetic recording layer. The magnetic random access memory thus-structured radiates heat generated in the magnetic recording layer by using the heat sink structure, suppressing the temperature increase caused by the write current flown in the in-plane direction.Type: GrantFiled: August 27, 2013Date of Patent: December 30, 2014Assignee: NEC CorporationInventors: Nobuyuki Ishiwata, Hideaki Numata, Norikazu Ohshima
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Patent number: 8791534Abstract: In a perpendicular magnetization domain wall motion MRAM in which the magnetizations of both ends of a magnetization free layer are pinned by magnetization pinned layers, the increase of a write current due to leakage magnetic field from the magnetization pinned layer is prevented. A first displacement is present between a first boundary line and a first vertical line, where a curve portion, which crosses a first magnetization free layer, of an outer circumferential line of a first magnetization pinned layer is the first boundary line, a segment which links a center of a magnetization free region and a center of a first magnetization pinned region is a first segment, and a segment, which is a vertical line of the first segment, and which comes in contact with the first boundary line is the first vertical line.Type: GrantFiled: June 16, 2011Date of Patent: July 29, 2014Assignee: NEC CorporationInventors: Shunsuke Fukami, Tetsuhiro Suzuki, Kiyokazu Nagahara, Nobuyuki Ishiwata, Norikazu Ohshima
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Patent number: 8787076Abstract: A magnetic memory according to the present invention has: a first underlayer; a second underlayer so formed on the first underlayer as to be in contact with the first underlayer; and a data storage layer so formed on the second underlayer as to be in contact with the second underlayer. The data storage layer is made of a ferromagnetic material having perpendicular magnetic anisotropy. A magnetization state of the data storage layer is changed by current driven domain wall motion.Type: GrantFiled: August 13, 2009Date of Patent: July 22, 2014Assignee: NEC CorporationInventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Kiyokazu Nagahara, Norikazu Ohshima
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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
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Patent number: 8687414Abstract: A magnetic memory cell includes: a magnetization recording layer; and a magnetic tunneling junction section. The magnetization recording layer includes a ferromagnetic layer with perpendicular magnetic anisotropy. The magnetic tunneling junction section is used for reading information in the magnetization recording layer. The magnetization recording layer includes two domain wall moving areas.Type: GrantFiled: December 24, 2009Date of Patent: April 1, 2014Assignee: NEC CorporationInventors: Kiyokazu Nagahara, Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Norikazu Ohshima
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Patent number: 8625327Abstract: A domain wall motion type MRAM has: a magnetic recording layer 10 being a ferromagnetic layer having perpendicular magnetic anisotropy; a pair of current supply terminals 14a and 14b connected to the magnetic recording layer 10 for supplying a current to the magnetic recording layer 10; and an anti-ferromagnetic layer 45 being in contact with a first region R1 of the magnetic recording layer 10. The first region R1 includes a part of a current supply region RA of the magnetic recording layer 10 that is between the pair of current supply terminals 14a and 14b.Type: GrantFiled: July 2, 2009Date of Patent: January 7, 2014Assignee: NEC CorporationInventors: Tetsuhiro Suzuki, Shunsuke Fukami, Kiyokazu Nagahara, Norikazu Oshima, Nobuyuki Ishiwata
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Publication number: 20130341744Abstract: A magnetic random access memory according to the present invention is provided with: a magnetic recording layer including a magnetization free region having a reversible magnetization, wherein a write current is flown through the magnetic recording layer in an in-plane direction; a magnetization fixed layer having a fixed magnetization; a non-magnetic layer provided between the magnetization free region and the magnetization fixed layer; and a heat sink structure provided to be opposed to the magnetic recording layer and having a function of receiving and radiating heat generated in the magnetic recording layer. The magnetic random access memory thus-structured radiates heat generated in the magnetic recording layer by using the heat sink structure, suppressing the temperature increase caused by the write current flown in the in-plane direction.Type: ApplicationFiled: August 27, 2013Publication date: December 26, 2013Applicant: NEC CorporationInventors: Nobuyuki ISHIWATA, Hideaki NUMATA, Norikazu OHSHIMA
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Patent number: 8592930Abstract: A magnetic memory element includes: a first magnetization free layer; a non-magnetic layer; a reference layer; a first magnetization fixed layer group; and a first blocking layer. The first magnetization free layer is composed of ferromagnetic material with perpendicular magnetic anisotropy and includes a first magnetization fixed region, a second magnetization fixed region and a magnetization free region. The non-magnetic layer is provided near the first magnetization free layer. The reference layer is composed of ferromagnetic material and provided on the non-magnetic layer. The first magnetization fixed layer group is provided near the first magnetization fixed region. The first blocking layer is provided being sandwiched between the first magnetization fixed layer group and the first magnetization fixed region or in the first magnetization fixed layer group.Type: GrantFiled: October 21, 2010Date of Patent: November 26, 2013Assignee: NEC CorporationInventors: Shunsuke Fukami, Tetsuhiro Suzuki, Kiyokazu Nagahara, Norikazu Ohshima, Nobuyuki Ishiwata
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Publication number: 20130285700Abstract: A non-volatile logic operation device includes an operation unit that is connected to a first input terminal, a second input terminal, and an output terminal, includes an operation layer, a first non-magnetic layer, and a reference layer, and outputs from the output terminal a result of a logic operation on signals applied at the first input terminal and the second input terminal, and a control unit that is connected to a third input terminal, and includes a control layer. The control unit is arranged in the vicinity of the operation unit.Type: ApplicationFiled: January 5, 2012Publication date: October 31, 2013Inventors: Shunsuke Fukami, Nobuyuki Ishiwata
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Patent number: 8565011Abstract: An initialization method is provided for a magnetic memory element including: a data recording layer having perpendicular magnetic anisotropy which includes: a first magnetization fixed region, a second magnetization fixed region, and a magnetization free region coupled to the first magnetization fixed region and the second magnetization fixed region, the data recording layer being structure so that the coercive force of the first magnetization fixed region being different from that of the second magnetization fixed region. The initialization method includes steps of: directing the magnetizations of the first magnetization fixed region, the second magnetization fixed region and the magnetization free region in the same direction; and applying a magnetic field having both components perpendicular to and parallel to the magnetic anisotropy of the data recording layer to the data recording layer.Type: GrantFiled: October 29, 2009Date of Patent: October 22, 2013Assignee: NEC CorporationInventors: Shunsuke Fukami, Kiyokazu Nagahara, Tetsuhiro Suzuki, Nobuyuki Ishiwata, Norikazu Ohshima
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Patent number: 8559214Abstract: A magnetic memory cell is provided with a magnetization record layer and a magnetic tunnel junction section. The magnetization record layer is a ferromagnetic layer having a perpendicular magnetic anisotropy. The magnetic tunnel junction section is used to read data from the magnetization record layer. The magnetization record layer has a plurality of domain wall motion regions.Type: GrantFiled: December 24, 2009Date of Patent: October 15, 2013Assignee: NEC CorporationInventors: Shunsuke Fukami, Kiyokazu Nagahara, Tetsuhiro Suzuki, Nobuyuki Ishiwata, Norikazu Ohshima
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Patent number: 8547733Abstract: A magnetic random access memory according to the present invention is provided with: a magnetic recording layer including a magnetization free region having a reversible magnetization, wherein a write current is flown through the magnetic recording layer in an in-plane direction; a magnetization fixed layer having a fixed magnetization; a non-magnetic layer provided between the magnetization free region and the magnetization fixed layer; and a heat sink structure provided to be opposed to the magnetic recording layer and having a function of receiving and radiating heat generated in the magnetic recording layer. The magnetic random access memory thus-structured radiates heat generated in the magnetic recording layer by using the heat sink structure, suppressing the temperature increase caused by the write current flown in the in-plane direction.Type: GrantFiled: August 21, 2012Date of Patent: October 1, 2013Assignee: NEC CorporationInventors: Nobuyuki Ishiwata, Hideaki Numata, Norikazu Ohshima
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Patent number: 8537604Abstract: A magnetoresistance element is provided with: a magnetization recording layer that is a ferromagnetic layer. The magnetization recording layer includes: a magnetization reversal region having a reversible magnetization; a first magnetization fixed region connected to a first boundary of the magnetization reversal region and having a magnetization direction fixed in a first direction; and a second magnetization fixed region connected to a second boundary of the magnetization reversal region and having a magnetization direction fixed in a second direction. At least one magnetization reversal facilitation structure which is a structure in which a magnetization is reversed more easily than the remaining portion is provided for a portion of the second magnetization fixed region.Type: GrantFiled: October 16, 2009Date of Patent: September 17, 2013Assignee: NEC CorporationInventors: Tetsuhiro Suzuki, Shunsuke Fukami, Kiyokazu Nagahara, Norikazu Ohshima, Nobuyuki Ishiwata
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Patent number: 8526222Abstract: A magnetic random access memory according to the present invention is provided with: a magnetic recording layer including a magnetization free region having a reversible magnetization, wherein a write current is flown through the magnetic recording layer in an in-plane direction; a magnetization fixed layer having a fixed magnetization; a non-magnetic layer provided between the magnetization free region and the magnetization fixed layer; and a heat sink structure provided to be opposed to the magnetic recording layer and having a function of receiving and radiating heat generated in the magnetic recording layer. The magnetic random access memory thus-structured radiates heat generated in the magnetic recording layer by using the heat sink structure, suppressing the temperature increase caused by the write current flown in the in-plane direction.Type: GrantFiled: September 7, 2012Date of Patent: September 3, 2013Assignee: NEC CorporationInventors: Nobuyuki Ishiwata, Hideaki Numata, Norikazu Ohshima
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Patent number: 8514616Abstract: A magnetoresistive effect element includes: a magnetization free layer; a non-magnetic insertion layer provided adjacent to the magnetization free layer; a magnetic insertion layer provided adjacent to the non-magnetic insertion layer and opposite to the magnetization free layer with respect to the non-magnetic insertion layer; a spacer layer provided adjacent to the magnetic insertion layer and opposite to the non-magnetic insertion layer with respect to the magnetic insertion layer; and a first magnetization fixed layer provided adjacent to the spacer layer and opposite to the magnetic insertion layer with respect to the spacer layer. The magnetization free layer and the first magnetization fixed layer have magnetization components in directions approximately perpendicular to a film surface. The magnetization free layer includes two magnetization fixed portions and a domain wall motion portion arranged between the two magnetization fixed portions.Type: GrantFiled: February 15, 2010Date of Patent: August 20, 2013Assignee: NEC CorporationInventors: Nobuyuki Ishiwata, Norikazu Ohshima, Shunsuke Fukami, Kiyokazu Nagahara, Tetsuhiro Suzuki
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Patent number: 8503222Abstract: A non-volatile logic circuit includes an input section, a control section and an output section. The input section has perpendicular magnetic anisotropy and has a ferromagnetic layer whose magnetization state is changeable. The control section includes a ferromagnetic layer. The output section is provided in a neighborhood of the input section and the control section and includes a magnetic tunnel junction element whose magnetization state is changeable. The magnetization state of the input section is changed based on the magnetization state. A magnetization state of the magnetic tunnel junction element of the output section which state is changed based on the magnetization state of the ferromagnetic material of the control section and the magnetization state of the ferromagnetic material of the input section.Type: GrantFiled: January 21, 2010Date of Patent: August 6, 2013Assignee: NEC CorporationInventors: Tetsuhiro Suzuki, Shunsuke Fukami, Kiyokazu Nagahara, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Noboru Sakimura, Ryusuke Nebashi