Patents by Inventor Masahiko Nakayama

Masahiko Nakayama 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).

  • Publication number: 20120243305
    Abstract: According to one embodiment, a magnetoresistance effect element includes first and second magnetic layers having an axis of easy magnetization in a direction perpendicular to a film surface, a first nonmagnetic layer formed between the first and second magnetic layers, a first interface magnetic layer formed between the first magnetic layer and the first nonmagnetic layer, and a second nonmagnetic layer formed in the first interface magnetic layer and having an amorphous structure. An electric current flowing through the first magnetic layer, the first nonmagnetic layer, and the second magnetic layer makes a magnetization direction in the first magnetic layer variable.
    Type: Application
    Filed: March 28, 2012
    Publication date: September 27, 2012
    Inventors: Masahiko NAKAYAMA, Katsuya NISHIYAMA
  • Publication number: 20120241884
    Abstract: 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: Application
    Filed: March 28, 2012
    Publication date: September 27, 2012
    Inventors: Hisanori AIKAWA, Tadashi Kai, Masahiko Nakayama, Sumio Ikegawa, Naoharu Shimomura, Eiji Kitagawa, Tatsuya Kishi, Jyunichi Ozeki, Hiroaki Yoda, Satoshi Yanagi
  • Publication number: 20120230091
    Abstract: According to one embodiment, a magnetic memory includes at least one memory cell including a magnetoresistive element, and first and second electrodes. The element includes a first magnetic layer, a tunnel barrier layer, a second magnetic layer, and a third magnetic layer provided on the second magnetic layer and having a magnetization antiparallel to the magnetization direction of the second magnetic layer. A diameter of an upper surface of the first magnetic layer is smaller than that of a lower surface of the tunnel barrier layer. A diameter of a lower surface of the second magnetic layer is not more than that of an upper surface of the tunnel barrier layer.
    Type: Application
    Filed: March 21, 2012
    Publication date: September 13, 2012
    Inventors: Satoshi YANAGI, Eiji KITAGAWA, Masahiko NAKAYAMA, Jyunichi OZEKI, Hisanori AIKAWA, Naoharu SHIMOMURA, Masatoshi YOSHIKAWA, Minoru AMANO, Shigeki TAKAHASHI, Hiroaki YODA
  • Patent number: 8223533
    Abstract: 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: Grant
    Filed: September 10, 2009
    Date of Patent: July 17, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Jyunichi Ozeki, Naoharu Shimomura, Sumio Ikegawa, Tadashi Kai, Masahiko Nakayama, Hisanori Aikawa, Tatsuya Kishi, Hiroaki Yoda, Eiji Kitagawa, Masatoshi Yoshikawa
  • Publication number: 20120163070
    Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a perpendicular and variable magnetization, a second magnetic layer with a perpendicular and invariable magnetization, and a first nonmagnetic layer between the first and second magnetic layer. The first magnetic layer has a laminated structure of first and second ferromagnetic materials. A magnetization direction of the first magnetic layer is changed by a current which pass through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer. A perpendicular magnetic anisotropy of the second ferromagnetic material is smaller than that of the first ferromagnetic material. A film thickness of the first ferromagnetic material is thinner than that of the second ferromagnetic material.
    Type: Application
    Filed: February 28, 2012
    Publication date: June 28, 2012
    Inventors: Toshihiko Nagase, Tadashi Kai, Katsuya Nishiyama, Eiji Kitagawa, Tadaomi Daibou, Masahiko Nakayama, Makoto Nagamine, Shigeto Fukatsu, Masatoshi Yoshikawa, Hiroaki Yoda
  • Patent number: 8208292
    Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.
    Type: Grant
    Filed: January 3, 2012
    Date of Patent: June 26, 2012
    Assignees: Kabushiki Kaisha Toshiba, National Institute of Advanced Industrial Science and Technology
    Inventors: Tadashi Kai, Katsuya Nishiyama, Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Tadaomi Daibou, Makoto Nagamine, Masahiko Nakayama, Naoharu Shimomura, Hiroaki Yoda, Kei Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
  • Patent number: 8173447
    Abstract: 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: Grant
    Filed: August 5, 2010
    Date of Patent: May 8, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomasa Ueda, Hisanori Aikawa, Masatoshi Yoshikawa, Naoharu Shimomura, Masahiko Nakayama, Sumio Ikegawa, Keiji Hosotani, Makoto Nagamine
  • Patent number: 8169817
    Abstract: A magnetoresistive device includes: a magnetic recording layer including a first magnetic layer having perpendicular magnetic anisotropy, and a second magnetic layer having in-plane magnetic anisotropy and being exchange-coupled to the first magnetic layer, Curie temperature of the second magnetic layer being lower than Curie temperature of the first magnetic layer, and the magnetic recording layer having a magnetization direction perpendicular to a film plane; a magnetic reference layer having a magnetization direction which is perpendicular to a film plane and is invariable; and a nonmagnetic layer provided between the magnetic recording layer and the magnetic reference layer. The magnetization direction of the magnetic recording layer is changeable by spin-polarized electrons caused by flowing current between the magnetic recording layer and the magnetic reference layer in a direction perpendicular to the film plane.
    Type: Grant
    Filed: March 2, 2010
    Date of Patent: May 1, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masahiko Nakayama, Hiroaki Yoda, Tadashi Kai, Hisanori Aikawa, Katsuya Nishiyama, Jyunichi Ozeki
  • Publication number: 20120099369
    Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.
    Type: Application
    Filed: January 3, 2012
    Publication date: April 26, 2012
    Inventors: Tadashi KAI, Katsuya Nishiyama, Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Tadaomi Daibou, Makoto Nagamine, Masahiko Nakayama, Naoharu Shimomura, Hiroaki Yoda, Kei Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
  • Patent number: 8139403
    Abstract: Certain embodiments provide a spin memory including a memory cell including a ferromagnetic stacked film that has a stacked structure in which a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, a second nonmagnetic layer, and a third ferromagnetic layer are stacked in this order or reverse order, the third ferromagnetic layer and the second ferromagnetic layer being antiferromagnetically exchange-coupled via the second nonmagnetic layer. The ferromagnetic stacked film includes a current path in which a first and second write currents flow from the first ferromagnetic layer to the third ferromagnetic layer to write a first and second magnetization states into the first ferromagnetic layer respectively, and the second write current is higher than the first write current.
    Type: Grant
    Filed: September 20, 2010
    Date of Patent: March 20, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa, Hideyuki Sugiyama, Hisanori Aikawa, Masahiko Nakayama, Tatsuya Kishi, Hiroaki Yoda, Yoshiaki Saito
  • Patent number: 8120948
    Abstract: 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: Grant
    Filed: September 17, 2009
    Date of Patent: February 21, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masahiko Nakayama, Hisanori Aikawa, Tsuneo Inaba, Kenji Tsuchida, Sumio Ikegawa, Hiroaki Yoda, Naoharu Shimomura
  • Patent number: 8107281
    Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.
    Type: Grant
    Filed: September 10, 2010
    Date of Patent: January 31, 2012
    Assignees: Kabushiki Kaisha Toshiba, National Institute of Advanced Industrial Science and Technology
    Inventors: Tadashi Kai, Katsuya Nishiyama, Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Tadaomi Daibou, Makoto Nagamine, Masahiko Nakayama, Naoharu Shimomura, Hiroaki Yoda, Kei Yakushiji, Shinji Yuasa, Hitoshi Kubota, Taro Nagahama, Akio Fukushima, Koji Ando
  • Patent number: 8098514
    Abstract: A magnetoresistive element includes a first reference layer having magnetic anisotropy perpendicular to a film surface, and an invariable magnetization, a recording layer having a stacked structure formed by alternately stacking magnetic layers and nonmagnetic layers, magnetic anisotropy perpendicular to a film surface, and a variable magnetization, and an intermediate layer provided between the first reference layer and the recording layer, and containing a nonmagnetic material. The magnetic layers include a first magnetic layer being in contact with the intermediate layer and a second magnetic layer being not in contact with the intermediate layer. The first magnetic layer contains an alloy containing cobalt (Co) and iron (Fe), and has a film thickness larger than that of the second magnetic layer.
    Type: Grant
    Filed: September 18, 2008
    Date of Patent: January 17, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Katsuya Nishiyama, Tadashi Kai, Masahiko Nakayama, Makoto Nagamine, Minoru Amano, Masatoshi Yoshikawa, Tatsuya Kishi, Hiroaki Yoda
  • Publication number: 20120008381
    Abstract: A magnetoresistive element which records information by supplying spin-polarized electrons to a magnetic material, includes a first pinned layer which is made of a magnetic material and has a first magnetization directed in a direction perpendicular to a film surface, a free layer which is made of a magnetic material and has a second magnetization directed in the direction perpendicular to the film surface, the direction of the second magnetization reversing by the spin-polarized electrons, and a first nonmagnetic layer which is provided between the first pinned layer and the free layer. A saturation magnetization Ms of the free layer satisfies a relationship 0?Ms<?{square root over ( )}{Jw/(6?At)}. Jw is a write current density, t is a thickness of the free layer, A is a constant.
    Type: Application
    Filed: September 15, 2011
    Publication date: January 12, 2012
    Inventors: Toshihiko NAGASE, Masatoshi Yoshikawa, Eiji Kitagawa, Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Hiroaki Yoda
  • Publication number: 20110309418
    Abstract: 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: Application
    Filed: July 18, 2011
    Publication date: December 22, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masahiko NAKAYAMA, Tadashi Kai, Sumio Ikegawa, Hiroaki Yoda, Tatsuya Kishi
  • Patent number: 8036025
    Abstract: A magnetoresistive element which records information by supplying spin-polarized electrons to a magnetic material, includes a first pinned layer which is made of a magnetic material and has a first magnetization directed in a direction perpendicular to a film surface, a free layer which is made of a magnetic material and has a second magnetization directed in the direction perpendicular to the film surface, the direction of the second magnetization reversing by the spin-polarized electrons, and a first nonmagnetic layer which is provided between the first pinned layer and the free layer. A saturation magnetization Ms of the free layer satisfies a relationship 0?Ms<?{square root over ( )}{Jw/(6?At)}. Jw is a write current density, t is a thickness of the free layer, A is a constant.
    Type: Grant
    Filed: January 12, 2010
    Date of Patent: October 11, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Masatoshi Yoshkawa, Eiji Kitagawa, Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Hiroaki Yoda
  • Publication number: 20110228596
    Abstract: Certain embodiments provide a spin memory including a memory cell including a ferromagnetic stacked film that has a stacked structure in which a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, a second nonmagnetic layer, and a third ferromagnetic layer are stacked in this order or reverse order, the third ferromagnetic layer and the second ferromagnetic layer being antiferromagnetically exchange-coupled via the second nonmagnetic layer. The ferromagnetic stacked film includes a current path in which a first and second write currents flow from the first ferromagnetic layer to the third ferromagnetic layer to write a first and second magnetization states into the first ferromagnetic layer respectively, and the second write current is higher than the first write current.
    Type: Application
    Filed: September 20, 2010
    Publication date: September 22, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa, Hideyuki Sugiyama, Hisanori Aikawa, Masahiko Nakayama, Tatsuya Kishi, Hiroaki Yoda, Yoshiaki Saito
  • Patent number: 8023386
    Abstract: An optical pickup apparatus for reproducing information from an optical disk, includes: a semiconductor laser applying a beam to an optical disk having two recording layers through an objective lens; and a light receiving device to which light reflected from the optical disk is directed through the objective lens and a beam splitting device, wherein: the beam splitting device has two first light receiving areas for detecting a push-pull signal and a second light receiving area for detecting a focus error signal, and a configuration is provided such that the center of the optical axis of the reflected light in the beam splitting device is made to lie within the second light receiving area for detecting the focus error signal.
    Type: Grant
    Filed: February 21, 2008
    Date of Patent: September 20, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiko Nakayama, Hiroshi Akiyama
  • Patent number: 8014193
    Abstract: 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: Grant
    Filed: March 3, 2009
    Date of Patent: September 6, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masahiko Nakayama, Tadashi Kai, Sumio Ikegawa, Hiroaki Yoda, Tatsuya Kishi
  • Patent number: 8009465
    Abstract: 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: Grant
    Filed: February 2, 2009
    Date of Patent: August 30, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Yoshiaki Fukuzumi, Toshihiko Nagase, Sumio Ikegawa, Hiroaki Yoda