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: 20030168673
    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: Application
    Filed: August 14, 2002
    Publication date: September 11, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
  • Publication number: 20030011463
    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: Application
    Filed: June 24, 2002
    Publication date: January 16, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hitoshi Iwasaki, Katsuhiko Koui, Masatoshi Yoshikawa, Hiromi Yuasa, Hideaki Fukuzawa, Masashi Sahashi
  • Publication number: 20030011945
    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: Application
    Filed: June 21, 2002
    Publication date: January 16, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Masashi Sahashi
  • Patent number: 6495275
    Abstract: A magnetoresistance effect element includes a free layer, a pinned layer and a non-magnetic intermediate layer interposed between the free layer and the pinned layer. Additionally, a metal barrier layer is provided adjacent to the first magnetic layer. An electron reflecting layer located adjacent to the metal barrier layer contains at least one selected from oxides, nitrides, carbides, fluorides, chlorides, sulfides and borides.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: December 17, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuzo Kamiguchi, Akiko Saito, Katsuhiko Koui, Masatoshi Yoshikawa, Hiromi Yuasa, Hideaki Fukuzawa, Susumu Hashimoto, Hitoshi Iwasaki, Hiroaki Yoda, Masashi Sahashi
  • Publication number: 20020048128
    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: October 19, 2001
    Publication date: April 25, 2002
    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: 20020048690
    Abstract: Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording/reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween.
    Type: Application
    Filed: October 10, 2001
    Publication date: April 25, 2002
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
  • Publication number: 20020009616
    Abstract: According to the another aspect of the invention, a magnetoresistance effect element having a magnetoresistance effect film which includes a crystal growth controlling layer as one of films therein, characterized in that a roughness along a boundary between films overlying said crystal growth controlling layer is smaller than a roughness along a boundary between films underlying said crystal growth controlling layer is provided. According to the another aspect of the invention, a magnetoresistance effect element comprising a free layer, pinned layer and a non-magnetic intermediate layer interposed between said free layer and pinned layer, characterized in further comprising a metal barrier layer provided adjacent to said first magnetic layer, and an electron reflecting layer located adjacent to said metal barrier layer and containing at least one selected from oxides, nitrides, carbides, fluorides, chlorides, sulfides and borides is also provided.
    Type: Application
    Filed: August 13, 2001
    Publication date: January 24, 2002
    Inventors: Yuzo Kamiguchi, Akiko Saito, Katsuhiko Koui, Masatoshi Yoshikawa, Hiromi Yuasa, Hideaki Fukuzawa, Susumu Hashimoto, Hitoshi Iwasaki, Hiroaki Yoda, Masashi Sahashi
  • Patent number: 6338899
    Abstract: Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording/reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween.
    Type: Grant
    Filed: June 14, 1999
    Date of Patent: January 15, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
  • Patent number: 6313973
    Abstract: A magnetoresistive element comprises an exchange coupling film having a under layer, an antiferromagnetic film and a ferromagnetic film, which are laminated in that order, the under layer including a metal having a face centered cubic crystal structure or hexagonal closest packing crystal structure which have a longer nearest neighbor atomic distance than that of the antiferromagnetic film. With this construction, it is possible to improve the exchange coupling field and to satisfy a stable output over a long period of time. A magnetoresistive element having a dual spin valve structure has a magnetization adjusting layer, which is antiferromagnetically connected to a pinned layer via an anti-parallel connection layer, to adjust the value of the product of the saturation magnetization of each of the magnetization adjusting layer and the pinned layer by the thickness thereof.
    Type: Grant
    Filed: June 30, 1999
    Date of Patent: November 6, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Fuke, Kazuhiro Saito, Katsuhiko Koui, Hideaki Fukuzawa, Akiko Saito, Hitoshi Iwasaki
  • Patent number: 6303218
    Abstract: According to the another aspect of the invention, a magnetoresistance effect element having a magnetoresistance effect film which includes a crystal growth controlling layer as one of films therein, characterized in that a roughness along a boundary between films overlying said crystal growth controlling layer is smaller than a roughness along a boundary between films underlying said crystal growth controlling layer is provided. According to the another aspect of the invention, a magnetoresistance effect element comprising a free layer, pinned layer and a non-magnetic intermediate layer interposed between said free layer and pinned layer, characterized in further comprising a metal barrier layer provided adjacent to said first magnetic layer, and an electron reflecting layer located adjacent to said metal barrier layer and containing at least one selected from oxides, nitrides, carbides, fluorides, chlorides, sulfides and borides is also provided.
    Type: Grant
    Filed: March 22, 1999
    Date of Patent: October 16, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuzo Kamiguchi, Akiko Saito, Katsuhiko Koui, Masatoshi Yoshikawa, Hiromi Yuasa, Hideaki Fukuzawa, Susumu Hashimoto, Hitoshi Iwasaki, Hiroaki Yoda, Masashi Sahashi