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: 20090140358
    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: Application
    Filed: February 2, 2009
    Publication date: June 4, 2009
    Inventors: Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Yoshiaki Fukuzumi, Toshihiko Nagase, Sumio Ikegawa, Hiroaki Yoda
  • Patent number: 7525837
    Abstract: A magnetoresistive effect element includes a nonmagnetic layer having mutually facing first and second surfaces. A reference layer is provided on the first surface and has a fixed magnetization direction. A magnetization variable layer is provided on the second surface, has variable magnetization direction, and has a planer shape including a rectangular part, a first projected part, and a second projected part. The rectangular part has mutually facing first and second longer sides and mutually facing first and second shorter sides. The first projected part projects from the first longer side at a position shifted from the center toward the first shorter side. The second projected part projects from the second longer side at a position shifted from the center toward the second shorter side.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: April 28, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadashi Kai, Masahiko Nakayama, Sumio Ikegawa, Yoshiaki Fukuzumi, Yoshihisa Iwata
  • Patent number: 7518906
    Abstract: A magneto-resistive element according to an aspect of the present invention includes a free layer whose magnetized state changes and a pinned layer whose magnetized state is fixed. The free layer comprises first and second ferromagnetic layers and a non-magnetic layer which is arranged between the first and second ferromagnetic layers. An intensity of exchange coupling between the first and second ferromagnetic layers is set so that an astroid curve in a hard axis direction opens.
    Type: Grant
    Filed: March 20, 2006
    Date of Patent: April 14, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Sumio Ikegawa, Masahiko Nakayama, Tadashi Kai, Eiji Kitagawa, Hiroaki Yoda
  • Patent number: 7518907
    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: January 25, 2008
    Date of Patent: April 14, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Yoshiaki Fukuzumi, Toshihiko Nagase, Sumio Ikegawa, Hiroaki Yoda
  • Publication number: 20090080239
    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: Application
    Filed: September 18, 2008
    Publication date: March 26, 2009
    Inventors: Toshihiko Nagase, Katsuya Nishiyama, Tadashi Kai, Masahiko Nakayama, Makoto Nagamine, Minoru Amano, Masatoshi Yoshikawa, Tatsuya Kishi, Hiroaki Yoda
  • Publication number: 20080203708
    Abstract: A front face distance is obtained by measuring the position of a front face of an instrument panel held by an end effecter of a robot. An error on an optical axis, at the position of the front face is obtained based on the front face distance. Based on the error, the position of the instrument panel is adjusted so that a focal point of a laser meets the position at a predetermined depth defined with the front face as the standard. A back face of the instrument panel is irradiated with a laser to form a fine hole of a fragile section.
    Type: Application
    Filed: March 6, 2006
    Publication date: August 28, 2008
    Inventors: Tokuji Okumura, Kazushiro Wakabayashi, Mitsutaka Igaue, Hisashi Masuda, Yutaka Ebato, Masahiko Nakayama
  • Patent number: 7414880
    Abstract: A magnetoresistive effect element includes a nonmagnetic layer having mutually facing first and second surfaces. A reference layer is provided on the first surface and has a fixed magnetization direction. A magnetization variable layer is provided on the second surface, has variable magnetization direction, and has a planer shape including a rectangular part, a first projected part, and a second projected part. The rectangular part has mutually facing first and second longer sides and mutually facing first and second shorter sides. The first projected part projects from the first longer side at a position shifted from the center toward the first shorter side. The second projected part projects from the second longer side at a position shifted from the center toward the second shorter side.
    Type: Grant
    Filed: March 20, 2006
    Date of Patent: August 19, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadashi Kai, Masahiko Nakayama, Sumio Ikegawa, Yoshiaki Fukuzumi, Yoshihisa Iwata
  • Patent number: 7411263
    Abstract: 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: Grant
    Filed: March 27, 2006
    Date of Patent: August 12, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masahiko Nakayama, Tadashi Kai, Sumio Ikegawa, Yoshiaki Fukuzumi, Tatsuya Kishi
  • Publication number: 20080180859
    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: Application
    Filed: January 15, 2008
    Publication date: July 31, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomomasa UEDA, Hisanori AIKAWA, Masatoshi YOSHIKAWA, Naoharu SHIMOMURA, Masahiko NAKAYAMA, Sumio IKEGAWA, Keiji HOSOTANI, Makoto NAGAMINE
  • Publication number: 20080165657
    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: Application
    Filed: February 21, 2008
    Publication date: July 10, 2008
    Inventors: Masahiko Nakayama, Hiroshi Akiyama
  • Publication number: 20080158740
    Abstract: 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: Application
    Filed: February 26, 2008
    Publication date: July 3, 2008
    Inventors: Masahiko NAKAYAMA, Tadashi Kai, Sumio Ikegawa, Yoshiaki Fukuzumi, Tatsuya Kishi
  • Publication number: 20080130176
    Abstract: A magnetoresistive effect element includes a nonmagnetic layer having mutually facing first and second surfaces. A reference layer is provided on the first surface and has a fixed magnetization direction. A magnetization variable layer is provided on the second surface, has variable magnetization direction, and has a planer shape including a rectangular part, a first projected part, and a second projected part. The rectangular part has mutually facing first and second longer sides and mutually facing first and second shorter sides. The first projected part projects from the first longer side at a position shifted from the center toward the first shorter side. The second projected part projects from the second longer side at a position shifted from the center toward the second shorter side.
    Type: Application
    Filed: January 25, 2008
    Publication date: June 5, 2008
    Applicant: KABUSHHIKI KAISHA TOSHIBA
    Inventors: Tadashi KAI, Masahiko Nakayama, Sumio Ikegawa, Yoshiaki Fukuzumi, Yoshihisa Iwata
  • Publication number: 20080131732
    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: Application
    Filed: January 25, 2008
    Publication date: June 5, 2008
    Inventors: Masahiko NAKAYAMA, Tadashi Kai, Tatsuya Kishi, Yoshiaki Fukuzumi, Toshihiko Nagase, Sumio Ikegawa, Hiroaki Yoda
  • Patent number: 7359295
    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: January 28, 2004
    Date of Patent: April 15, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiko Nakayama, Hiroshi Akiyama
  • Patent number: 7355884
    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: October 7, 2005
    Date of Patent: April 8, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Yoshiaki Fukuzumi, Toshihiko Nagase, Sumio Ikegawa, Hiroaki Yoda
  • Patent number: 7328040
    Abstract: Mobile communication equipment comprises a power amplifier for amplifying a transmission signal and a feedback circuit for providing feedback to allow the above-described power amplifier to output a transmission-power set value.
    Type: Grant
    Filed: February 17, 2005
    Date of Patent: February 5, 2008
    Assignee: NEC Corporation
    Inventor: Masahiko Nakayama
  • Patent number: 7245524
    Abstract: A magnetic memory device includes a first write wiring which runs in a first direction, a second write wiring which runs in a second direction different from the first direction, and a magnetoresistive element which is arranged at an intersection between the first and second write wirings, has a fixed layer, a recording layer, and a magnetoresistive layer sandwiched between the fixed layer and the recording layer, and has an axis of easy magnetization obliquely with respect to the first and second directions, the recording layer including a first ferromagnetic layer, a second ferromagnetic layer, and a first nonmagnetic layer sandwiched between the first and second ferromagnetic layers, in which first magnetization of the first ferromagnetic layer and second magnetization of the second ferromagnetic layer are ferromagnetically coupled, and a ferro-coupling constant C of a ferromagnetic coupling is 0.0001 erg/cm2?C?0.2 erg/cm2.
    Type: Grant
    Filed: October 21, 2005
    Date of Patent: July 17, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Yoda, Tadashi Kai, Masahiko Nakayama, Sumio Ikegawa, Tatsuya Kishi
  • Publication number: 20070096229
    Abstract: A magnetoresistive element includes a magnetic recording layer which records information as a magnetization direction changes upon supplying a bidirectional current in an out-of-plane direction, a magnetic reference layer which has a fixed magnetization direction, and a nonmagnetic layer which is provided between the magnetic recording layer and the magnetic reference layer. The magnetic recording layer includes an interface magnetic layer which is provided in contact with the nonmagnetic layer and has a first magnetic anisotropy energy, and a magnetic stabilizing layer which has a second magnetic anisotropy energy higher than the first magnetic anisotropy energy.
    Type: Application
    Filed: October 23, 2006
    Publication date: May 3, 2007
    Inventors: Masatoshi Yoshikawa, Toshihiko Nagase, Eiji Kitagawa, Hiroaki Yoda, Tatsuya Kishi, Masahiko Nakayama
  • Publication number: 20070086121
    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/(6nAt)}. Jw is a write current density, t is a thickness of the free layer, A is a constant.
    Type: Application
    Filed: September 22, 2006
    Publication date: April 19, 2007
    Inventors: Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Hiroaki Yoda
  • Publication number: 20070070689
    Abstract: A magneto-resistive element according to an aspect of the present invention includes a free layer whose magnetized state changes and a pinned layer whose magnetized state is fixed. The free layer comprises first and second ferromagnetic layers and a non-magnetic layer which is arranged between the first and second ferromagnetic layers. An intensity of exchange coupling between the first and second ferromagnetic layers is set so that an astroid curve in a hard axis direction opens.
    Type: Application
    Filed: March 20, 2006
    Publication date: March 29, 2007
    Inventors: Sumio Ikegawa, Masahiko Nakayama, Tadashi Kai, Eiji Kitagawa, Hiroaki Yoda