Patents by Inventor Masatoshi Yoshikawa

Masatoshi Yoshikawa 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: 8363462
    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: September 15, 2011
    Date of Patent: January 29, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Hiroaki Yoda
  • Publication number: 20130005148
    Abstract: According to one embodiment, a method of manufacturing a semiconductor device, the method includes forming a pillar on a base layer, forming a insulating layer on the base layer to cover the pillar by using GCIB method, where a lowermost portion of an upper surface of the insulating layer is lower than an upper surface of the pillar, and polishing the insulating layer and the pillar to expose a head of the pillar by using CMP method, where an end point of the polishing is the lowermost portion of the upper surface of the insulating layer.
    Type: Application
    Filed: March 23, 2012
    Publication date: January 3, 2013
    Inventors: Yasuyuki Sonoda, Kyoichi Suguro, Masatoshi Yoshikawa, Koji Yamakawa, Katsuaki Natori, Daisuke Ikeno
  • Publication number: 20130001652
    Abstract: According to one embodiment, a magnetoresistive element includes a storage layer having a variable and perpendicular magnetization, a tunnel barrier layer on the storage layer, a reference layer having an invariable and perpendicular magnetization on the tunnel barrier layer, a hard mask layer on the reference layer, and a sidewall spacer layer on sidewalls of the reference layer and the hard mask layer. An in-plane size of the reference layer is smaller than an in-plane size of the storage layer. A difference between the in-plane sizes of the storage layer and the reference layer is 2 nm or less. The sidewall spacer layer includes a material selected from a group of a diamond, DLC, BN, SiC, B4C, Al2O3 and AlN.
    Type: Application
    Filed: March 23, 2012
    Publication date: January 3, 2013
    Inventors: Masatoshi Yoshikawa, Satoshi Seto, Hideaki Harakawa, Jyunichi Ozeki, Tatsuya Kishi, Keiji Hosotani
  • Patent number: 8299552
    Abstract: A magnetoresistive element includes a first underlying layer having an NaCl structure and containing a nitride orienting in a (001) plane, a first magnetic layer provided on the first underlying layer, having magnetic anisotropy perpendicular to a film surface, having an L10 structure, and containing a ferromagnetic alloy orienting in a (001) plane, a first nonmagnetic layer provided on the first magnetic layer, and a second magnetic layer provided on the first nonmagnetic layer and having magnetic anisotropy perpendicular to a film surface.
    Type: Grant
    Filed: September 18, 2008
    Date of Patent: October 30, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Katsuya Nishiyama, Tadaomi Daibou, Tatsuya Kishi, Hiroaki Yoda
  • 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
  • Publication number: 20120197295
    Abstract: A bioabsorbable suture according to the present invention is characterized in that the suture is manufactured from monofilaments or multifilaments spun from a spinning raw solution containing one or two or more component(s) selected from the group consisting of chitin, chitosan, and derivatives thereof and a degrading enzyme for the component(s), and the degrading enzyme exists on a surface of the suture and in the suture.
    Type: Application
    Filed: April 9, 2012
    Publication date: August 2, 2012
    Applicants: TOTAI CO., LTD., OMIKENSHI CO., LTD.
    Inventors: Masatoshi Yoshikawa, Hideki Kajita, Takeshi Noguchi, Juichi Kasai
  • Publication number: 20120183491
    Abstract: A method for producing an amylose-containing rayon fiber, comprising the steps of: mixing an aqueous alkaline solution of amylose with viscose to obtain a mixed liquid, spinning the mixed liquid to obtain an amylose-containing rayon fiber, and bringing the amylose-containing rayon fiber into contact with iodine or polyiodide ions, thereby allowing an amylose in the amylose-containing rayon fiber to make a clathrate including the iodine or polyiodide ions, wherein the amylose is an enzymatically synthesized amylose having a weight average molecular weight of 3×104 or more and 2×105 or less. A method for collecting iodine from brackish water with high efficiency utilizing the amylase-containing rayon fibers.
    Type: Application
    Filed: June 17, 2010
    Publication date: July 19, 2012
    Applicants: OMIKENSHI CO., LTD., KANTO NATURAL GAS DEVELOPMENT CO., LTD., EZAKI GLICO CO., LTD.
    Inventors: Osamu Inoue, Masatoshi Yoshikawa, Mieko Takaku, Tatsuo Kaiho, Mitsuru Taguchi, Haruyo Sambe, Yoshinobu Terada, Takeshi Takaha
  • 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
  • Patent number: 8218355
    Abstract: A magnetoresistive element includes an underlying layer having a cubic or tetragonal crystal structure oriented in a (001) plane, a first magnetic layer provided on the underlying layer, having perpendicular magnetic anisotropy, and having an fct structure oriented in a (001) plane, a non-magnetic layer provided on the first magnetic layer, and a second magnetic layer provided on the non-magnetic layer, and having perpendicular magnetic anisotropy. An in-plane lattice constant a1 of the underlying layer and an in-plane lattice constant a2 of the first magnetic layer satisfy the following equation in which b is a magnitude of Burgers vector of the first magnetic layer, ? is an elastic modulus of the first magnetic layer, and hc is a thickness of the first magnetic layer. |?{square root over (2)}×a1/2?a2|/a2<b×{ln (hc/b)+1}/{2?×hc×(1+?)}.
    Type: Grant
    Filed: March 24, 2009
    Date of Patent: July 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Eiji Kitagawa, Masatoshi Yoshikawa, Toshihiko Nagase, Tadaomi Daibou, Makoto Nagamine, Katsuya Nishiyama, Tatsuya Kishi, Hiroaki Yoda
  • 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
  • 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
  • Publication number: 20120088125
    Abstract: A magnetoresistive element according to an embodiment includes: a base layer; a first magnetic layer formed on the base layer and having a changeable magnetization direction with an easy axis of magnetization in a direction perpendicular to a film plane; a first nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the first nonmagnetic layer and having a fixed magnetization layer with an easy axis of magnetization in a direction perpendicular to the film plane. The first magnetic layer includes a ferrimagnetic layer having a DO22 structure or an L10 structure, the ferrimagnetic layer has a c-axis oriented in a direction perpendicular to the film plane, and the magnetization direction of the first magnetic layer is changeable by a current flowing through the first magnetic layer, the first nonmagnetic layer, and the second magnetic layer.
    Type: Application
    Filed: September 19, 2011
    Publication date: April 12, 2012
    Applicants: NATIONAL UNIVERSITY CORPORATION TOHOKU UNIVERSITY, KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuya NISHIYAMA, Wu Feng, Chunlan Feng, Shigemi Mizukami, Terunobu Miyazaki, Hiroaki Yoda, Tadashi Kai, Tatsuya Kishi, Daisuke Watanabe, Mikihiko Oogane, Yasuo Ando, Masatoshi Yoshikawa, Toshihiko Nagase, Eiji Kitagawa, Tadaomi Daibou, Makoto Nagamine
  • Patent number: 8154915
    Abstract: The present invention provides a low-resistance magnetoresistive element of a spin-injection write type. A crystallization promoting layer that promotes crystallization is formed in contact with an interfacial magnetic layer having an amorphous structure, so that crystallization is promoted from the side of a tunnel barrier layer, and the interface between the tunnel barrier layer and the interfacial magnetic layer is adjusted. With this arrangement, it is possible to form a magnetoresistive element that has a low resistance so as to obtain a desired current value, and has a high TMR ratio.
    Type: Grant
    Filed: May 20, 2011
    Date of Patent: April 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Eiji Kitagawa, Tadaomi Daibou, Toshihiko Nagase, Tatsuya Kishi, Hiroaki Yoda
  • Patent number: 8143684
    Abstract: 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: Grant
    Filed: January 25, 2011
    Date of Patent: March 27, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Makoto Nagamine, Toshihiko Nagase, Sumio Ikegawa, Katsuya Nishiyama, Masatoshi Yoshikawa
  • Patent number: 8139405
    Abstract: The present invention provides a low-resistance magnetoresistive element of a spin-injection write type. A crystallization promoting layer that promotes crystallization is formed in contact with an interfacial magnetic layer having an amorphous structure, so that crystallization is promoted from the side of a tunnel barrier layer, and the interface between the tunnel barrier layer and the interfacial magnetic layer is adjusted. With this arrangement, it is possible to form a magnetoresistive element that has a low resistance so as to obtain a desired current value, and has a high TMR ratio.
    Type: Grant
    Filed: May 5, 2011
    Date of Patent: March 20, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Eiji Kitagawa, Tadaomi Daibou, Toshihiko Nagase, Tatsuya Kishi, Hiroaki Yoda
  • 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