Patents by Inventor Sumio Ikegawa
Sumio Ikegawa 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: 8347175Abstract: According to one embodiment, a magnetic memory includes a magnetoresistive effect element including a first magnetic layer invariable in magnetization direction, a second magnetic layer variable in magnetization direction, and an intermediate layer between the first magnetic layer and the second magnetic layer, an error detecting and correcting circuit which detects whether first data in the magnetoresistive effect element includes any error and which outputs error-corrected second data when the first data includes an error, a writing circuit which generates one of the first write current including a first pulse width and the second write current including a second pulse width greater than the first pulse width, and a control circuit which controls the writing circuit to pass the second write current through the magnetoresistive effect element when the second data is written into the magnetoresistive effect element.Type: GrantFiled: September 21, 2010Date of Patent: January 1, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Sumio Ikegawa, Naoharu Shimomura, Kenji Tsuchida, Hiroaki Yoda
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Patent number: 8279663Abstract: A magnetoresistance effect element includes: a first ferromagnetic layer having invariable magnetization perpendicular to a film plane; a second ferromagnetic layer having variable magnetization perpendicular to the film plane; a first nonmagnetic layer interposed between the first ferromagnetic layer and the second ferromagnetic layer; a third ferromagnetic layer provided on an opposite side of the second ferromagnetic layer from the first nonmagnetic layer, and having variable magnetization parallel to the film plane; and a second nonmagnetic layer interposed between the second and third ferromagnetic layers.Type: GrantFiled: July 18, 2011Date of Patent: October 2, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Nakayama, Tadashi Kai, Sumio Ikegawa, Hiroaki Yoda, Tatsuya Kishi
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Publication number: 20120241884Abstract: According to one embodiment, a magnetic memory includes a magnetoresistive element. The magnetoresistive element includes a reference layer having an invariable magnetization direction, a storage layer having a variable magnetization direction, and a spacer layer provided between the reference layer and the storage layer. The storage layer has a multilayered structure including first and second magnetic layers, the second magnetic layer is provided between the first magnetic layer and the spacer layer and has a magnetic anisotropy energy lower than that of the first magnetic layer, and an exchange coupling constant Jex between the first magnetic layer and the second magnetic layer is not more than 5 erg/cm2.Type: ApplicationFiled: March 28, 2012Publication date: September 27, 2012Inventors: Hisanori AIKAWA, Tadashi Kai, Masahiko Nakayama, Sumio Ikegawa, Naoharu Shimomura, Eiji Kitagawa, Tatsuya Kishi, Jyunichi Ozeki, Hiroaki Yoda, Satoshi Yanagi
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Patent number: 8223533Abstract: A magnetic memory includes a magnetoresistive effect device comprising: a first ferromagnetic layer that has magnetic anisotropy in a direction perpendicular to a film plane thereof; a first nonmagnetic layer that is provided on the first ferromagnetic layer; a first reference layer that is provided on the first nonmagnetic layer, has magnetic anisotropy in a direction perpendicular to a film plane thereof, has magnetization antiparallel to a magnetization direction of the first ferromagnetic layer, and has a film thickness that is 1/5.2 to 1/1.Type: GrantFiled: September 10, 2009Date of Patent: July 17, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Jyunichi Ozeki, Naoharu Shimomura, Sumio Ikegawa, Tadashi Kai, Masahiko Nakayama, Hisanori Aikawa, Tatsuya Kishi, Hiroaki Yoda, Eiji Kitagawa, Masatoshi Yoshikawa
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Patent number: 8173447Abstract: A magnetoresistive element includes: a magnetization free layer having a first plane and a second plane located on the opposite side from the first plane, and having a variable magnetization direction; a magnetization pinned layer provided on the first plane side of the magnetization free layer, and having a pinned magnetization direction; a first tunnel barrier layer provided between the magnetization free layer and the magnetization pinned layer; a second tunnel barrier layer provided on the second plane of the magnetization free layer; and a non-magnetic layer provided on a plane on the opposite side of the second tunnel barrier layer from the magnetization free layer. The magnetization direction of the magnetization free layer is variable by applying current between the magnetization pinned layer and the non-magnetic layer, and a resistance ratio between the first tunnel barrier layer and the second tunnel barrier layer is in a range of 1:0.25 to 1:4.Type: GrantFiled: August 5, 2010Date of Patent: May 8, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Tomomasa Ueda, Hisanori Aikawa, Masatoshi Yoshikawa, Naoharu Shimomura, Masahiko Nakayama, Sumio Ikegawa, Keiji Hosotani, Makoto Nagamine
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Patent number: 8143684Abstract: A magnetoresistive element includes a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential, a second magnetic layer, a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer, and a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential.Type: GrantFiled: January 25, 2011Date of Patent: March 27, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Makoto Nagamine, Toshihiko Nagase, Sumio Ikegawa, Katsuya Nishiyama, Masatoshi Yoshikawa
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Patent number: 8120948Abstract: A data writing method for a magnetoresistive effect element of an aspect of the present invention including generating a write current in which a falling period from the start of a falling edge to the end of the falling edge is longer than a rising period from the start of a rising edge to the end of the rising edge, and flowing the write current through the magnetoresistive effect element which comprises a first magnetic layer having an invariable magnetizing direction, a second magnetic layer having a variable magnetizing direction, and a tunnel barrier layer provided between the first magnetic layer and the second magnetic layer, to change the magnetizing direction of the second magnetic layer.Type: GrantFiled: September 17, 2009Date of Patent: February 21, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Nakayama, Hisanori Aikawa, Tsuneo Inaba, Kenji Tsuchida, Sumio Ikegawa, Hiroaki Yoda, Naoharu Shimomura
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Publication number: 20110309418Abstract: A magnetoresistance effect element includes: a first ferromagnetic layer having invariable magnetization perpendicular to a film plane; a second ferromagnetic layer having variable magnetization perpendicular to the film plane; a first nonmagnetic layer interposed between the first ferromagnetic layer and the second ferromagnetic layer; a third ferromagnetic layer provided on an opposite side of the second ferromagnetic layer from the first nonmagnetic layer, and having variable magnetization parallel to the film plane; and a second nonmagnetic layer interposed between the second and third ferromagnetic layers.Type: ApplicationFiled: July 18, 2011Publication date: December 22, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Masahiko NAKAYAMA, Tadashi Kai, Sumio Ikegawa, Hiroaki Yoda, Tatsuya Kishi
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Publication number: 20110254114Abstract: A magnetoresistive effect element includes a first ferromagnetic layer formed above a substrate, a second ferromagnetic layer formed above the first ferromagnetic layer, an insulating layer interposed between the first ferromagnetic layer and the second ferromagnetic layer and formed of a metal oxide, and a first nonmagnetic metal layer interposed between the insulating layer and the second ferromagnetic layer and in contact with a surface of the insulating layer on the side of the second ferromagnetic layer, the first nonmagnetic metal layer containing the same metal element as the metal oxide.Type: ApplicationFiled: June 29, 2011Publication date: October 20, 2011Inventors: Makoto Nagamine, Keiji Hosotani, Hisanori Aikawa, Tomomasa Ueda, Sumio Ikegawa
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Patent number: 8014193Abstract: A magnetoresistance effect element includes: a first ferromagnetic layer having invariable magnetization perpendicular to a film plane; a second ferromagnetic layer having variable magnetization perpendicular to the film plane; a first nonmagnetic layer interposed between the first ferromagnetic layer and the second ferromagnetic layer; a third ferromagnetic layer on an opposite side of the second ferromagnetic layer from the first nonmagnetic layer, and having variable magnetization parallel to the film plane; and a second nonmagnetic layer interposed between the second and third ferromagnetic layers.Type: GrantFiled: March 3, 2009Date of Patent: September 6, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Nakayama, Tadashi Kai, Sumio Ikegawa, Hiroaki Yoda, Tatsuya Kishi
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Patent number: 8009465Abstract: A magnetoresistive element includes a first ferromagnetic layer having a first magnetization, the first magnetization having a first pattern when the magnetoresistive element is half-selected during a first data write, a second pattern when the magnetoresistive element is selected during a second data write, and a third pattern of residual magnetization, the first pattern being different from the second and third pattern, a second ferromagnetic layer having a second magnetization, and a nonmagnetic layer arranged between the first ferromagnetic layer and the second ferromagnetic layer and having a tunnel conductance changing dependent on a relative angle between the first magnetization and the second magnetization.Type: GrantFiled: February 2, 2009Date of Patent: August 30, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Yoshiaki Fukuzumi, Toshihiko Nagase, Sumio Ikegawa, Hiroaki Yoda
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Publication number: 20110116305Abstract: A magnetoresistive element includes a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential, a second magnetic layer, a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer, and a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential.Type: ApplicationFiled: January 25, 2011Publication date: May 19, 2011Inventors: Makoto NAGAMINE, Toshihiko Nagase, Sumio Ikegawa, Katsuya Nishiyama, Masatoshi Yoshikawa
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Publication number: 20110078538Abstract: According to one embodiment, a magnetic memory includes a magnetoresistive effect element including a first magnetic layer invariable in magnetization direction, a second magnetic layer variable in magnetization direction, and an intermediate layer between the first magnetic layer and the second magnetic layer, an error detecting and correcting circuit which detects whether first data in the magnetoresistive effect element includes any error and which outputs error-corrected second data when the first data includes an error, a writing circuit which generates one of the first write current including a first pulse width and the second write current including a second pulse width greater than the first pulse width, and a control circuit which controls the writing circuit to pass the second write current through the magnetoresistive effect element when the second data is written into the magnetoresistive effect element.Type: ApplicationFiled: September 21, 2010Publication date: March 31, 2011Inventors: Sumio Ikegawa, Naoharu Shimomura, Kenji Tsuchida, Hiroaki Yoda
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Patent number: 7898846Abstract: A magnetoresistive element includes a first magnetic layer which includes a first surface and a second surface and has a first standard electrode potential, a second magnetic layer, a barrier layer which is provided between the second magnetic layer and the first surface of the first magnetic layer, and a nonmagnetic cap layer which contacts the second surface of the first magnetic layer and is formed from an alloy of a first metal material and a second metal material, the first metal material having a second standard electrode potential lower than the first standard electrode potential, the second metal material having a third standard electrode potential higher than the first standard electrode potential.Type: GrantFiled: May 22, 2009Date of Patent: March 1, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Makoto Nagamine, Toshihiko Nagase, Sumio Ikegawa, Katsuya Nishiyama, Masatoshi Yoshikawa
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Patent number: 7894246Abstract: A magnetoresistive element includes: a magnetization free layer having a first plane and a second plane located on the opposite side from the first plane, and having a variable magnetization direction; a magnetization pinned layer provided on the first plane side of the magnetization free layer, and having a pinned magnetization direction; a first tunnel barrier layer provided between the magnetization free layer and the magnetization pinned layer; a second tunnel barrier layer provided on the second plane of the magnetization free layer; and a non-magnetic layer provided on a plane on the opposite side of the second tunnel barrier layer from the magnetization free layer. The magnetization direction of the magnetization free layer is variable by applying current between the magnetization pinned layer and the non-magnetic layer, and a resistance ratio between the first tunnel barrier layer and the second tunnel barrier layer is in a range of 1:0.25 to 1:4.Type: GrantFiled: January 15, 2008Date of Patent: February 22, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Tomomasa Ueda, Hisanori Aikawa, Masatoshi Yoshikawa, Naoharu Shimomura, Masahiko Nakayama, Sumio Ikegawa, Keiji Hosotani, Makoto Nagamine
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Patent number: 7875903Abstract: A magnetic memory device includes a magnetoresistive element and a first wiring layer. The magnetoresistive element includes a fixed layer, a recording layer, and a non-magnetic layer interposed therebetween. The first wiring layer extends in a first direction and generates a magnetic field for recording data in the magnetoresistive element. The recording layer includes a base portion extending in a second direction rotated from the first direction by an angle falling within a range of more than 0° to not more than 20°, and first and second projections projecting from the first and second sides of the base portion in a third direction perpendicular to the second direction. The third and fourth sides of the base portion are inclined with respect to the third direction in the same rotational direction as a rotational direction in which the second direction is rotated.Type: GrantFiled: February 26, 2008Date of Patent: January 25, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Nakayama, Tadashi Kai, Sumio Ikegawa, Yoshiaki Fukuzumi, Tatsuya Kishi
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Publication number: 20100315864Abstract: A magnetoresistive element includes: a magnetization free layer having a first plane and a second plane located on the opposite side from the first plane, and having a variable magnetization direction; a magnetization pinned layer provided on the first plane side of the magnetization free layer, and having a pinned magnetization direction; a first tunnel barrier layer provided between the magnetization free layer and the magnetization pinned layer; a second tunnel barrier layer provided on the second plane of the magnetization free layer; and a non-magnetic layer provided on a plane on the opposite side of the second tunnel barrier layer from the magnetization free layer. The magnetization direction of the magnetization free layer is variable by applying current between the magnetization pinned layer and the non-magnetic layer, and a resistance ratio between the first tunnel barrier layer and the second tunnel barrier layer is in a range of 1:0.25 to 1:4.Type: ApplicationFiled: August 5, 2010Publication date: December 16, 2010Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomomasa UEDA, Hisanori Aikawa, Masatoshi Yoshikawa, Naoharu Shimomura, Masahiko Nakayama, Sumio Ikegawa, Keiji Hosotani, Makoto Nagamine
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Publication number: 20100246244Abstract: A magnetoresistive effect memory of an aspect of the present invention including a magnetoresistive effect element including a first magnetic layer having an invariable magnetization direction, a second magnetic layer having a variable magnetization direction, and an interlayer provided between the first magnetic layer and the second magnetic layer, and a reading circuit which passes a pulse-shaped read current through the magnetoresistive effect element to read data stored in the magnetoresistive effect element, wherein the pulse width of the read current is shorter than a period from an initial state to a cooperative coherent precession movement of magnetizations included in the second magnetic layer.Type: ApplicationFiled: March 29, 2010Publication date: September 30, 2010Inventors: Naoharu SHIMOMURA, Eiji Kitagawa, Sumio Ikegawa, Yoshihisa Iwata
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Publication number: 20100080050Abstract: A magnetic memory includes a magnetoresistive effect device comprising: a first ferromagnetic layer that has magnetic anisotropy in a direction perpendicular to a film plane thereof; a first nonmagnetic layer that is provided on the first ferromagnetic layer; a first reference layer that is provided on the first nonmagnetic layer, has magnetic anisotropy in a direction perpendicular to a film plane thereof, has magnetization antiparallel to a magnetization direction of the first ferromagnetic layer, and has a film thickness that is 1/5.2 to 1/1.Type: ApplicationFiled: September 10, 2009Publication date: April 1, 2010Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Jyunichi OZEKI, Naoharu SHIMOMURA, Sumio IKEGAWA, Tadashi KAI, Masahiko NAKAYAMA, Hisanori AIKAWA, Tatsuya KISHI, Hiroaki YODA, Eiji KITAGAWA, Masatoshi YOSHIKAWA
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Publication number: 20100078763Abstract: A resistance-change memory includes an interlayer insulating film, a lower electrode layer, a fixed layer, a first insulating film, a recording layer, a second insulating film, a conducting layer and an interconnect. The interlayer insulating film is formed on a semiconductor substrate and has a step. The lower electrode layer is formed on the interlayer insulating film including the step. The fixed layer is formed on the lower electrode layer and has invariable magnetization. The first insulating film is formed on the fixed layer. The recording layer is formed on part of the first insulating film and has variable magnetization. The second insulating film is over the recording layer and in contact with the first insulating film. The conducting layer is formed on the second insulating film. The interconnect is connected to the conducting layer.Type: ApplicationFiled: September 14, 2009Publication date: April 1, 2010Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Keiji HOSOTANI, Yoshiaki ASAO, Kuniaki SUGIURA, Masatoshi YOSHIKAWA, Sumio IKEGAWA, Shigeki TAKAHASHI, Minoru AMANO