Patents by Inventor Katsuhiko Koui

Katsuhiko Koui 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: 20100073806
    Abstract: It is made possible to improve the recording resolution. A magnetic recording head includes: a magnetic pole that has a first magnetic portion including an air bearing surface, and generates a write magnetic field; and a spin torque oscillator that is formed on the air bearing surface of the magnetic pole, and is formed with a stack structure including a first magnetic layer, a second magnetic layer, and a nonmagnetic layer interposed between the first magnetic layer and the second magnetic layer, the second magnetic layer generating a high-frequency magnetic field when current is applied between the first magnetic layer and the second magnetic layer.
    Type: Application
    Filed: September 15, 2009
    Publication date: March 25, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuhiko Koui, Hitoshi Iwasaki, Masayuki Takagishi, Kenichiro Yamada, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Soichi Oikawa
  • Publication number: 20100007996
    Abstract: It is made possible to reduce the write magnetic field generated from the main magnetic pole toward the spin torque oscillator, so as to reduce the variation in the oscillation characteristics of the spin torque oscillator, and reduce the current required for oscillation. The magnetic head assembly includes: a recording magnetic pole; a spin torque oscillator that has first and second magnetic layers, and an intermediate layer interposed between the first and second magnetic layers, the spin torque oscillator generating a high-frequency magnetic field by applying a current between the first and second magnetic layers; and a third magnetic layer that is placed adjacent to at least part of a side face of the second magnetic layer.
    Type: Application
    Filed: June 17, 2009
    Publication date: January 14, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hitoshi Iwasaki, Kenichiro Yamada, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Soichi Oikawa, Katsuhiko Koui
  • Publication number: 20100007992
    Abstract: A magnetic head assembly includes a magnetic recording head, a head slider, a suspension and an actuator arm. The magnetic recording head includes: a main magnetic pole; an adjustment magnetic pole provided together with the main magnetic pole; a spin torque oscillator; a main magnetic pole coil being wound around the main magnetic pole; and an adjustment magnetic pole coil being wound around the adjustment magnetic pole. At least part of the spin torque oscillator is provided between the main magnetic pole and the adjustment magnetic pole. A way of winding of the adjustment magnetic pole coil is different from a way of winding of the main magnetic pole coil. The magnetic recording head is mounted on the head slider. The head slider is mounted on one end of the suspension. The actuator arm is connected to the other end of the suspension.
    Type: Application
    Filed: May 26, 2009
    Publication date: January 14, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Soichi Oikawa, Katsuhiko Koui
  • Publication number: 20090316304
    Abstract: A magnetic head assembly includes a magnetic recording head, a main magnetic pole, a head slider, a suspension and an actuator arm. The magnetic recording head includes a main magnetic pole having an air bearing surface facing a magnetic recording medium; and a stacked structure having, a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. A stacked plane of the stacked structure is inclined with respect to the air bearing surface. The magnetic recording head is mounted on the head slider. The head slider is mounted on one end of the suspension. The actuator arm is connected to the other end of the suspension.
    Type: Application
    Filed: June 18, 2009
    Publication date: December 24, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomomi Funayama, Kenichiro Yamada, Katsuhiko Koui, Hitoshi Iwasaki, Masayuki Takagishi, Masahiro Takashita, Mariko Shimizu, Soichi Oikawa
  • Publication number: 20090310254
    Abstract: According to one embodiment, a recording track has a surface modification layer in the surface region. This surface modification layer has an anisotropic magnetic field Hk reduced from that of a region between adjacent recording tracks.
    Type: Application
    Filed: April 9, 2009
    Publication date: December 17, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Soichi OIKAWA, Hitoshi IWASAKI, Masayuki TAKAGISHI, Kenichiro YAMADA, Tomomi FUNAYAMA, Masahiro TAKASHITA, Katsuhiko KOUI, Mariko SHIMIZU
  • Publication number: 20090269618
    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: July 6, 2009
    Publication date: October 29, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuuzo KAMIGUCHI, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
  • Publication number: 20090257151
    Abstract: A spin valve structure for a spintronic device is disclosed and includes a composite seed layer made of at least Ta and a metal layer having a fcc(111) or hcp(001) texture to enhance perpendicular magnetic anisotropy (PMA) in an overlying (Co/Ni)x multilayer. The (Co/Ni)x multilayer is deposited by a low power and high Ar pressure process to avoid damaging Co/Ni interfaces and thereby preserving PMA. As a result, only a thin seed layer is required. PMA is maintained even after annealing at 220° C. for 10 hours. Examples of GMR and TMR spin valves are described and may be incorporated in spin transfer oscillators and spin transfer MRAMs. The free layer is preferably made of a FeCo alloy including at least one of Al, Ge, Si, Ga, B, C, Se, Sn, or a Heusler alloy, or a half Heusler alloy to provide high spin polarization and a low magnetic damping coefficient.
    Type: Application
    Filed: June 19, 2009
    Publication date: October 15, 2009
    Inventors: Kunliang Zhang, Min Li, Yuchen Zhou, Soichi Oikawa, Kenichiro Yamada, Katsuhiko Koui
  • Patent number: 7561383
    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: Grant
    Filed: September 17, 2008
    Date of Patent: July 14, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
  • Patent number: 7525776
    Abstract: A magnetoresistive element has a magnetization pinned layer a magnetization direction of which is substantially pinned in one direction, a magnetization free layer a magnetization direction of which varies depending on an external field, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating the insulating layer, the magnetization pinned layer or magnetization free layer located under the spacer layer comprising crystal grains separated by grain boundaries extending across a thickness thereof, in which, supposing that an in-plane position of one end of each of the crystal grains is set to 0 and an in-plane position of a grain boundary adjacent to the other end of the crystal grain is set to 100, the current path corresponding the crystal grain is formed on a region in a range between 20 and 80 of the in-plane position.
    Type: Grant
    Filed: November 9, 2005
    Date of Patent: April 28, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Hiromi Yuasa, Katsuhiko Koui, Hitoshi Iwasaki
  • Patent number: 7525772
    Abstract: A magnetoresistive device includes a magnetoresistive film and a pair of electrodes for applying a sense current substantially perpendicularly to the magnetoresistive film. The magnetoresistive film includes a magnetization pinned film including a first ferromagnetic layer having a magnetization direction substantially pinned in one direction, a magnetization free film including a second ferromagnetic layer whose magnetization direction changes in accordance with an external magnetic field applied thereto, an intermediate layer formed between the magnetization pinned film and the magnetization free film and having an insulating film and a metal conduction portion extending in the film thickness direction of the insulating film, and a layer containing an electrovalent or covalent compound formed near the metal conduction portion.
    Type: Grant
    Filed: March 8, 2006
    Date of Patent: April 28, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsuhiko Koui, Takashi Tateyama, legal representative, Tomomi Funayama, Koichi Kubo, Hitoshi Iwasaki, Hideaki Fukuzawa, Kohichi Tateyama
  • Patent number: 7515386
    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: Grant
    Filed: March 27, 2006
    Date of Patent: April 7, 2009
    Assignee: Kabushiki Kaisa Toshiba
    Inventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
  • Patent number: 7514117
    Abstract: The present invention relates to a method for manufacturing a magnetoresistive element having a magnetization pinned layer, a magnetization free layer, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating into the insulating layer. A process of forming the spacer layer in the method includes depositing a first metal layer forming the metal paths, depositing a second metal layer on the first metal layer, performing a pretreatment of irradiating the second metal layer with an ion beam or a RF plasma of a rare gas, and converting the second metal layer into the insulating layer by means of supplying an oxidation gas or a nitriding gas.
    Type: Grant
    Filed: August 9, 2005
    Date of Patent: April 7, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Katsuhiko Koui, Hiromi Yuasa, Susumu Hashimoto, Hitoshi Iwasaki
  • Patent number: 7511927
    Abstract: A spin valve type magnetoresistive effect element for vertical electric conduction includes a magnetoresistive effect film in which a resistance adjustment layer made of a material containing conductive carriers not more than 1022/cm3 is inserted. Thus the resistance value of a portion in change of spin-relied conduction is raised to an adequate value, thereby to increase the resistance variable amount.
    Type: Grant
    Filed: November 21, 2005
    Date of Patent: March 31, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Masashi Sahashi
  • Publication number: 20090061105
    Abstract: The present invention relates to a method for manufacturing a magnetoresistive element having a magnetization pinned layer, a magnetization free layer, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating into the insulating layer. A process of forming the spacer layer in the method includes depositing a first metal layer forming the metal paths, depositing a second metal layer on the first metal layer, performing a pretreatment of irradiating the second metal layer with an ion beam or a RF plasma of a rare gas, and converting the second metal layer into the insulating layer by means of supplying an oxidation gas or a nitriding gas.
    Type: Application
    Filed: October 9, 2008
    Publication date: March 5, 2009
    Inventors: Hideaki FUKUZAWA, Katsuhiko Koui, Hiromi Yuasa, Susumu Hashimoto, Hitoshi Iwasaki
  • Publication number: 20090021869
    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: September 17, 2008
    Publication date: January 22, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuuzo KAMIGUCHI, Hiromi YUASA, Tomohiko NAGATA, Hiroaki YODA, Katsuhiko KOUI, Masatoshi YOSHIKAWA, Hitoshi IWASAKI, Masashi SAHASHI, Masayuki TAKAGISHI
  • Publication number: 20090002899
    Abstract: According to one embodiment, a magnetoresistive element includes a magnetization fixed layer, an intermediate layer provided on the magnetization fixed layer, a free layer provided on the intermediate layer, a separating layer composed of nonmagnetic metal and provided on the free layer, and a fluctuation compensated layer whose static magnetic coupling with the free layer is disconnected by the separating layer, whose magnetization direction is fixed so as to be antiparallel to the magnetization direction of the magnetization fixed layer, and provided on the separating layer.
    Type: Application
    Filed: June 27, 2008
    Publication date: January 1, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Katsuhiko Koui
  • Patent number: 7463456
    Abstract: A spin valve type magnetoresistive effect element for vertical electric conduction includes a magnetoresistive effect film in which a resistance adjustment layer made of a material containing conductive carriers not more than 1022/cm3 is inserted. Thus the resistance value of a portion in change of spin-relied conduction is raised to an adequate valve, thereby to increase the resistance variable amount.
    Type: Grant
    Filed: April 9, 2007
    Date of Patent: December 9, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Masashi Sahashi
  • Patent number: 7443004
    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: November 22, 2005
    Date of Patent: October 28, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
  • Patent number: 7405906
    Abstract: A magnetoresistance effect element of the dual spin valve type using a current-perpendicular-to-the-plane (CPP) system where a sensing current flows perpendicular to the stacked faces of a plurality of conductive layers, the magnetoresistance effect element comprises a first unit which includes a free layer and a first pinning layer, a second unit which includes the free layer shared with the first unit and a second pinning layer, a first current control layer which is provided in the first unit and limits the flow quantity of the sensing current, and a second current control layer which is provided in the second unit and limits the flow quantity of the sensing current.
    Type: Grant
    Filed: September 9, 2004
    Date of Patent: July 29, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Masayuki Takagishi, Katsuhiko Koui, Kohichi Tateyama
  • Patent number: 7379278
    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: April 7, 2006
    Date of Patent: May 27, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki