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).

  • 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
  • Patent number: 7200034
    Abstract: A magnetic memory device includes a magnetoresistance effect element, and a first write interconnection which is arranged under the magnetoresistance effect element and has a first interconnection layer and a first yoke layer, the first interconnection layer having a portion projecting toward the magnetoresistance effect element, and the first yoke layer including a first, a second, and third regions. And the device includes a second write interconnection which is arranged above the magnetoresistance effect element and has a second interconnection layer and a second yoke layer, the second interconnection layer having a portion projecting toward the magnetoresistance effect element, and the second yoke layer including a fourth, a fifth, and sixth regions.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: April 3, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Kajiyama, Tomomasa Ueda, Tatsuya Kishi, Hiroaki Yoda, Hisanori Aikawa, Masatoshi Yoshikawa
  • Patent number: 7196877
    Abstract: A magnetoresistive element includes a magnetoresistive film having a magnetization pinned layer, a magnetization free layer, and a nonmagnetic intermediate layer. A magnetization direction of the magnetization pinned layer is substantially fixed in an external magnetic field, a magnetization direction of the magnetization free layer is configured to change in the external magnetic field, and the nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer and has a stacked structure of a first non-metallic intermediate layer/a metal intermediate layer/a second non-metallic intermediate layer. The magnetoresistive element also includes a pair of electrodes coupled to the magnetoresistive film and is configured to provide a current in a direction substantially perpendicular to a surface of the magnetoresistive film.
    Type: Grant
    Filed: December 23, 2003
    Date of Patent: March 27, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Tomomi Funayama, Kohichi Tateyama, Hitoshi Iwasaki, Hideaki Fukuzawa
  • Patent number: 7190613
    Abstract: An MTJ element has two magnetic layers and a nonmagnetic layer. The resistance of the MTJ element, which varies depending on whether the two magnetic layers are magnetized parallel or antiparallel. In an MRAM adapted to write data into the MTJ element by causing a write wiring to generate induced magnetic flux and consequently changing the direction of magnetization of the recording layer, the MTJ element is a perpendicular MTJ element in which each of the two magnetic layers is magnetized in a direction perpendicular to its plane. The write wiring is placed in a direction perpendicular to the direction of the thickness of the MTJ element and applies a generated magnetic field to the magnetic layers of the MTJ element in the direction in which they are magnetized. Magnetic yokes hold the MTJ element in the direction of its thickness.
    Type: Grant
    Filed: June 8, 2004
    Date of Patent: March 13, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Hiroaki Yoda, Masatoshi Yoshikawa, Tadashi Kai, Tatsuya Kishi, Hisanori Aikawa, Tomomasa Ueda
  • Patent number: 7190558
    Abstract: In a CPP element using a metal intermediate layer excellent in shot noise and response to high frequencies unlike a TMR element, its magnetoresistive effect film includes a magnetic layer mainly made of a half-metal exhibiting ferromagnetism, ferrimagnetism or antiferromagnetism, and largely variable in way of conduction in response to spin direction of electrons.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: March 13, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Katsuhiko Koui, Masatoshi Yoshikawa, Hiromi Yuasa, Hideaki Fukuzawa, Masashi Sahashi
  • Publication number: 20070014149
    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: Application
    Filed: March 21, 2006
    Publication date: January 18, 2007
    Inventors: Makoto Nagamine, Toshihiko Nagase, Sumio Ikegawa, Katsuya Nishiyama, Masatoshi Yoshikawa
  • Patent number: 7145754
    Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer, and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film. The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: December 5, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
  • Patent number: 7130164
    Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film. The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: October 31, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
  • Patent number: 7126795
    Abstract: A magnetic recording head, a magnetic reproducing head, a magnetic recording apparatus comprising the magnetic recording head, and a magnetic reproducing apparatus comprising the magnetic reproducing head are described. The magnetic reproducing head having a magnetic gap at a medium-facing surface and includes a pair of magnetic yokes of ferromagnetic material, a magnetoresistance effect film, and a pair of biasing films. One of the pair of magnetic yokes has a magnetic tip at the medium-facing surface and also a rear portion recessed from the medium-facing surface and magnetically coupled to the magnetic tip. The magnetic tip has a first width in a track width direction at the medium-facing surface, and the rear portion has a second width in the track width direction wider than the first width. The magnetoresistance effect film is recessed from the medium-facing surface and is magnetically coupled to the pair of magnetic yokes of ferromagnetic material.
    Type: Grant
    Filed: August 27, 2001
    Date of Patent: October 24, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Kohichi Tateyama, Michiko Hara, Masatoshi Yoshikawa, Hiroaki Yoda
  • Patent number: 7116529
    Abstract: A magnetoresistive element has a magnetoresistive film and a pair of electrodes adapted to flow a sense current in a direction substantially perpendicular to a plane of the magnetoresistive film. The magnetoresistive film includes first and second magnetization free layers and first to fourth magnetization pinned layers with nonmagnetic intermediate layers interposed therebetween. The second magnetization pinned layer and the third magnetization pinned layer are formed between the second nonmagnetic intermediate layer and the third nonmagnetic intermediate layer. The directions of magnetization of the first and second magnetization pinned layers are substantially parallel to each other. The directions of magnetization of the third and fourth magnetization pinned layers are substantially parallel to each other. Further, the direction of magnetization of the second magnetization pinned layer is substantially antiparallel to the direction of magnetization of the third magnetization pinned layer.
    Type: Grant
    Filed: September 5, 2003
    Date of Patent: October 3, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi
  • Publication number: 20060181814
    Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film, The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.
    Type: Application
    Filed: April 7, 2006
    Publication date: August 17, 2006
    Inventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
  • Publication number: 20060164764
    Abstract: There is provided a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers to be controlled, and a magnetic head and magnetic recording and/or reproducing system using the same. In a magnetoresistance effect element wherein a sense current is caused to flow in a direction perpendicular to the plane of the film, a resistance regulating layer is provided in at least one of a pinned layer, a free layer and an non-magnetic intermediate layer. The resistance regulating layer contains, as a principal component, an oxide, a nitride, a fluoride, a carbide or a boride. The resistance regulating layer may be a continuous film or may have pin holes. Thus, it is possible to provide a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers, while effectively utilizing the scattering effect depending on spin.
    Type: Application
    Filed: March 27, 2006
    Publication date: July 27, 2006
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
  • Patent number: 7071522
    Abstract: In a spin valve type element, an interface insertion layer (32, 34) of a material exhibiting large spin-dependent interface scattering is inserted in a location of a magnetically pinned layer (16) or a magnetically free layer (20) closer to a nonmagnetic intermediate layer (18). A nonmagnetic back layer (36) may be additionally inserted as an interface not in contact with the nonmagnetic intermediate layer to increase the output by making use of spin-dependent interface scattering along the interface between the pinned layer and the nonmagnetic back layer or between the free layer and the nonmagnetic back layer.
    Type: Grant
    Filed: July 9, 2004
    Date of Patent: July 4, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
  • Patent number: 7072153
    Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film. The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.
    Type: Grant
    Filed: March 28, 2003
    Date of Patent: July 4, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
  • Publication number: 20060141121
    Abstract: The present invention is intended to provide a vegetable article which sustain initial characteristics inherent to a product with the use of vegetable articles such as hygroscopicity, texture, favorable smell and appearance and in which deformation, color change and emission of an unpleasant smell due to laundry or water washing are inhibited; a product containing the vegetable article; and a process for producing the vegetable article. To achieve this object, the following constitution is employed. Namely, a vegetable article has been subjected to a crosslinking treatment by using a crosslinking agent so as to inhibit worsening in the initial characteristics such as moisture content, bulk density and lightness. A product contains the above vegetable article. A process for producing the vegetable article characterized in that a crosslinking reaction with the use of a crosslinking agent is carried out to inhibit worsening in the initial characteristics of the vegetable article.
    Type: Application
    Filed: October 20, 2003
    Publication date: June 29, 2006
    Applicant: Toyo Boseki Kabushiki Kaisya
    Inventor: Masatoshi Yoshikawa
  • Publication number: 20060132984
    Abstract: A magnetic memory device includes a magnetoresistance effect element, and a first write interconnection which is arranged under the magnetoresistance effect element and has a first interconnection layer and a first yoke layer, the first interconnection layer having a portion projecting toward the magnetoresistance effect element, and the first yoke layer including a first, a second, and third regions. And the device includes a second write interconnection which is arranged above the magnetoresistance effect element and has a second interconnection layer and a second yoke layer, the second interconnection layer having a portion projecting toward the magnetoresistance effect element, and the second yoke layer including a fourth, a fifth, and sixth regions.
    Type: Application
    Filed: February 18, 2005
    Publication date: June 22, 2006
    Inventors: Takeshi Kajiyama, Tomomasa Ueda, Tatsuya Kishi, Hiroaki Yoda, Hisanori Aikawa, Masatoshi Yoshikawa
  • Patent number: 7064402
    Abstract: A magnetic random access memory concerning an example of the present invention comprises a magneto resistive element, a first insulating layer which covers side surfaces of the magneto resistive element, a second insulating layer which is arranged on the first insulating layer and has a first groove on the magneto resistive element, a write line which fills the first groove and is connected with the magneto resistive element, and a third insulating layer which is arranged between the first and second insulating layers except a bottom portion of the first groove and has an etching selection ratio with respect to at least the first and second insulating layers.
    Type: Grant
    Filed: July 27, 2005
    Date of Patent: June 20, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Kajiyama, Tomomasa Ueda, Tatsuya Kishi, Hisanori Aikawa, Masatoshi Yoshikawa, Yoshiaki Asao, Hiroaki Yoda
  • Publication number: 20060126228
    Abstract: A magnetoresistive head has a magnetoresistive film including first and second magnetization free layers, an intermediate layer-sandwiched between the first and second magnetization free layers, an underlayer and a protective layer, which are stacked in the order of the underlayer, the first magnetization free layer, the intermediate layer, the second magnetization free layer and the protective layer and arranged to be substantially perpendicular to the air-bearing surface, and a first electrode connected with the underlayer and a second electrode connected with the protective layer, the electrodes allowing a current to flow in a direction substantially perpendicular to the plane. Each magnetization direction of the first and second magnetization free layers is allowed to vary independently in response to a signal magnetic flux from a medium. The first and second magnetization free layers produce a magnetoresistance effect in accordance with the magnetization directions thereof.
    Type: Application
    Filed: February 13, 2006
    Publication date: June 15, 2006
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Yuzo Kamiguchi, Hiromi Yuasa
  • Patent number: 7061732
    Abstract: A magnetoresistive head has a magnetoresistive film including first and second magnetization free layers, an intermediate layer sandwiched between the first and second magnetization free layers, an underlayer and a protective layer, which are stacked in the order of the underlayer, the first magnetization free layer, the intermediate layer, the second magnetization free layer and the protective layer and arranged to be substantially perpendicular to the air-bearing surface, and a first electrode connected with the underlayer and a second electrode connected with the protective layer, the electrodes allowing a current to flow in a direction substantially perpendicular to the plane. Each magnetization direction of the first and second magnetization free layers is allowed to vary independently in response to a signal magnetic flux from a medium. The first and second magnetization free layers produce a magnetoresistance effect in accordance with the magnetization directions thereof.
    Type: Grant
    Filed: October 21, 2004
    Date of Patent: June 13, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Yuzo Kamiguchi, Hiromi Yuasa