Patents by Inventor Yuzo Kamiguchi

Yuzo Kamiguchi 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: 20020150791
    Abstract: A magnetoresistive device includes a magnetization pinned layer, a magnetization free layer, a nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer, and electrodes allowing a sense current to flow in a direction substantially perpendicular to the plane of the stack including the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer. At least one of the magnetization pinned layer and the magnetization free layer is substantially formed of a binary or ternary alloy represented by the formula FeaCobNic (where a+b+c=100 at %, and a≦75 at %, b≦75 at %, and c≦63 at %), or formed of an alloy having a body-centered cubic crystal structure.
    Type: Application
    Filed: February 1, 2002
    Publication date: October 17, 2002
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Yuzo Kamiguchi, Hitoshi Iwasaki, Masashi Sahashi
  • Publication number: 20020135954
    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: January 31, 2002
    Publication date: September 26, 2002
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Yuzo Kamiguchi, Hiromi Yuasa
  • Patent number: 6395388
    Abstract: The present invention provides an exchange coupling film having a stacked-film-structure consisting of a ferromagnetic film made of at least one material of Fe, Co and Ni, and an antiferromagnetic film, wherein the exchange coupling film made of a ferromagnetic material to which an element is added, is provided at the interface between the ferromagnetic film and the antiferromagnetic film so as to improve the lattice matching, which results in the enhancement of the exchange coupling force, and a magnetoresistance effect element including such an exchange coupling film as described above, and an electrode for supplying a current to the ferromagnetic film which constitutes the exchange coupling film.
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: May 28, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Yuichi Ohsawa, Reiko Kondoh, Susumu Hashimoto, Atsuhito Sawabe, Yuzo Kamiguchi, Masashi Sahashi, Hiromi Fuke
  • 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
  • Patent number: 6368706
    Abstract: The present invention provides an exchange coupling film having a stacked-film-structure consisting of a ferromagnetic film made of at least one material of Fe, Co and Ni, and an antiferromagnetic film, wherein the exchange coupling film made of a ferromagnetic material to which an element is added, is provided at the interface between the ferromagnetic film and the antiferromagnetic film so as to improve the lattice matching, which results in the enhancement of the exchange coupling force, and a magnetoresistance effect element including such an exchange coupling film as described above, and an electrode for supplying a current to the ferromagnetic film which constitutes the exchange coupling film.
    Type: Grant
    Filed: July 8, 1998
    Date of Patent: April 9, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Yuichi Ohsawa, Reiko Kondoh, Susumu Hashimoto, Atsuhito Sawabe, Yuzo Kamiguchi, Masashi Sahashi, Hiromi Fuke
  • Publication number: 20020039265
    Abstract: There is provided a magnetoresistance effect element capable of precisely defining the active region in a CPP type MR element and of effectively suppressing and eliminating the influence of a magnetic field due to current from an electrode, and a magnetic head and magnetic reproducing system using the same. The active region of the MR element is defined by the area of a portion through which a sense current flows. Moreover, the shape of the cross section of a pillar electrode or pillar non-magnetic material for defining the active region of the element is designed to extend along the flow of a magnetic flux so as to efficiently read only a signal from a track directly below the active region. When the magnetic field due to current from the pillar electrode can not be ignored, the magnetic flux from a recording medium asymmetrically enters yokes and the magnetization free layer of the MR element to some extent.
    Type: Application
    Filed: September 24, 2001
    Publication date: April 4, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiromi Yuasa, Hiroaki Yoda, Yuzo Kamiguchi, Tomohiko Nagata
  • Publication number: 20020039264
    Abstract: A yoke type magnetic head comprises a magnetoresistance effect film for sensing a signal magnetic field from a medium, a pair of magnetic yokes which are magnetically connected to the magnetoresistance effect film and which face each other via a magnetic gap, and a pair of electrodes which are connected to the magnetoresistance effect film so that a sense current in a thickness direction of the magnetoresistance effect film is applied thereto, one of the electrodes being formed in the magnetic gap. Thus, it is possible to prevent the lowering of the magnetic flux efficiency.
    Type: Application
    Filed: August 31, 2001
    Publication date: April 4, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuichi Ohsawa, Masatoshi Yoshikawa, Michiko Hara, Tomomi Funayama, Susumu Hashimoto, Kohichi Tateyama, Hiroaki Yoda, Yuzo Kamiguchi
  • Patent number: 6348274
    Abstract: A magnetoresistive element includes a pinned layer, free layer and non-magnetic spacer film between them. The pinned layer is made up of a first ferromagnetic metal layer, first non-metal layer on the first ferromagnetic metal layer, second non-metal layer on the first non-metal layer and different in composition from the first non-metal layer, and second ferromagnetic metal layer on the second non-metal layer. Thus, the magnetoresistive element, which may be used in a magnetic head of a magnetic recording apparatus, ensures a good bias property of the pinned film while maintaining a large MR changing rate of a specular spin valve structure, and it is simultaneously improved in soft magnetic property.
    Type: Grant
    Filed: December 27, 1999
    Date of Patent: February 19, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuzo Kamiguchi, Hiromi Yuasa, Masashi Sahashi, Hitoshi Iwasaki
  • Publication number: 20020015269
    Abstract: A magnetoresistance effect device comprises a magnetic multi-layer film having at least an antiferromagnetic film, a first ferromagnetic film, a non-magnetic film, and a second ferromagnetic film formed in the order on the front surface portion of the substrate, the magnetic multi-layer film having giant magnetoresistance effect, at least the second ferromagnetic film having a shape corresponding to a magnetic field detecting portion. The bias magnetic field applying films are disposed on a conductive film of the magnetic multi-layer film at outer portions of both edge portions of the magnetic field detecting portion of the magnetoresistance effective film. Alternatively, the second ferromagnetic film has a first portion corresponding to the magnetic field detecting portion and a second portion corresponding to the outer portions of both the edge portions of the magnetic field detecting portion, the film thickness-of the second portion being smaller than the film thickness of the first portion.
    Type: Application
    Filed: August 13, 2001
    Publication date: February 7, 2002
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Yuzo Kamiguchi, Hiromi Fuke, Kazuhiro Saito, 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
  • Publication number: 20010043448
    Abstract: A magnetoresistance effect device comprises a magnetic multi-layer film having at least an antiferromagnetic film, a first ferromagnetic film, a non-magnetic film, and a second ferromagnetic film formed in the order on the front surface portion of the substrate, the magnetic multi-layer film having giant magnetoresistance effect, at least the second ferromagnetic film having a shape corresponding to a magnetic field detecting portion. The bias magnetic field applying films are disposed on a conductive film of the magnetic multi-layer film at outer portions of both edge portions of the magnetic field detecting portion of the magnetoresistance effective film. Alternatively, the second ferromagnetic film has a first portion corresponding to the magnetic field detecting portion and a second portion corresponding to the outer portions of both the edge portions of the magnetic field detecting portion, the film thickness of the second portion being smaller than the film thickness of the first portion.
    Type: Application
    Filed: April 19, 2001
    Publication date: November 22, 2001
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Yuzo Kamiguchi, Hiromi Fuke, Kazuhiro Saito, Masashi Sahashi
  • 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
  • Publication number: 20010013999
    Abstract: A first layer region of a magnetically pinned layer in a spin valve structure, which is relatively remoter from a non-magnetic intermediate layer, is made of a ferromagnetic material containing at least one element selected from the group consisting of Cr (chrome), Rh (rhodium), Os (osmium), Re (rhenium), Si (silicon), Al (aluminum), Be (beryllium), Ga (gallium), Ge (germanium), Te (tellurium), B (boron), V (vanadium), Ru (ruthenium), Ir (iridium), W (tungsten), Mo (molybdenum), Au (gold), Pt (platinum), Ag (silver) and Cu (copper). Thereby, it is possible to provide a structure of the magnetically pinned layer, which can be readily made using a conventional deposition method and can ensure a sufficient electron reflecting effect on the part of the magnetically pinned layer, and to provide a magnetoresistive element using a spin valve film including the particular structure.
    Type: Application
    Filed: December 28, 2000
    Publication date: August 16, 2001
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuhiko Koi, Hitoshi Iwasaki, Yuzo Kamiguchi, Hiromi Fuke, Hideaki Fukuzawa
  • Patent number: 6256863
    Abstract: A magnetic yoke having a magnetic gap provided in the side of the surface facing the medium is disposed on the surface of a substrate. An MR film is disposed on the surface of the magnetic yoke substantially parallel to the substrate with a predetermined separation from the surface S facing the medium. At least both end portions of the MR film are magnetically coupled to the magnetic yoke. A pair of leads for supplying sensing current to the MR film have magnetic lead portions formed from the same magnetic layers as the magnetic yoke. The magnetic lead portions curb deterioration of MR head properties and yield reduction during formation of the leads. Furthermore, a bias magnetic field is applied to the magnetic yoke and the MR film at least during operation of the head. This bias magnetic field is for instance provided by a magnetic field induced by the electric current. Alternatively, a magnetic field induced by the electric current is applied while heat-processing the magnetic yoke.
    Type: Grant
    Filed: March 11, 1997
    Date of Patent: July 10, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuhiro Saito, Akiko Saito, Hitoshi Iwasaki, Akihiko Tsutai, Hiroaki Yoda, Tadahiko Kobayashi, Yuichi Ohsawa, Masahi Sahashi, Yuzo Kamiguchi
  • Patent number: 6159593
    Abstract: The present invention provides an exchange coupling film having a stacked-film-structure consisting of a ferromagnetic film made of at least one material of Fe, Co and Ni, and an antiferromagnetic film, wherein the exchange coupling film made of a ferromagnetic material to which an element is added, is provided at the interface between the ferromagnetic film and the antiferromagnetic film so as to improve the lattice matching, which results in the enhancement of the exchange coupling force, and a magnetoresistance effect element including such an exchange coupling film as described above, and an electrode for supplying a current to the ferromagnetic film which constitutes the exchange coupling film.
    Type: Grant
    Filed: April 16, 1998
    Date of Patent: December 12, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Yuichi Ohsawa, Reiko Kondoh, Susumu Hashimoto, Atsuhito Sawabe, Yuzo Kamiguchi, Masashi Sahashi, Hiromi Fuke
  • Patent number: 6157525
    Abstract: A magnetoresistive head includes a magnetoresistive effect element including a magnetoresistive film, which has a first ferromagnetic layer and a second ferromagnetic layer separated by a nonmagnetic layer. A magnetization direction of the first ferromagnetic layer is perpendicular to a magnetization direction of the second ferromagnetic layer when a signal magnetic field is zero. A pair of bias layers provide magnetic bias, and a top surface of each of the pair of bias layers faces a lower surface of each edge region of the magnetoresistive film. A pair of lead electrodes produce a current flow through the magnetoresistive film, and each of the pair of lead electrodes is disposed on or above the magnetoresistive film.
    Type: Grant
    Filed: June 29, 1999
    Date of Patent: December 5, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Reiko Kondoh, Hiroaki Yoda, Yuichi Ohsawa, Yuzo Kamiguchi, Susumu Hashimoto
  • Patent number: 6146776
    Abstract: A GMR head comprising a spin valve GMR film, which has a free layer containing a Co containing magnetic layer, and a hard magnetic biasing film for inputting a bias magnetic field to the spin valve GMR film. The hard magnetic biasing film is constituted of a film formed by laminating a hard magnetic layer on the magnetic under layer. The hard magnetic layer is disposed adjoining to edge portion of the spin valve GMR film through the magnetic under layer. The magnetic under layer has saturation magnetization Ms.sup.under which satisfies at least one condition of Ms.sup.under .gtoreq.Ms.sup.free and Ms.sup.under .gtoreq.Ms.sup.hard when saturation magnetization of the free layer is Ms.sup.free and saturation magnetization of the hard magnetic layer is Ms.sup.hard. In a MR head of this abutted junction structure, even when the track width is narrowed, occurrence of Barkhausen noise can be effectively suppressed.
    Type: Grant
    Filed: May 5, 1998
    Date of Patent: November 14, 2000
    Assignees: Kabushiki Kaisha Toshiba, TDK Corporation
    Inventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Naoyuki Inoue, Hitoshi Iwasaki, Noriyuki Ito, Taro Oike, Hiroaki Kawashima
  • Patent number: 6118624
    Abstract: A spin valve GMR element comprises a spin valve GMR film stacked in turn a pinned layer, a non-magnetic layer, and a free layer of which magnetization direction varies according to an external magnetic field, and a magnetic biasing film providing a bias magnetic field to the free layer. A spin valve GMR film can be a dual element type. A magnetic biasing film has a stacked film of a high saturation magnetization magnetic layer and a hard magnetic layer. The high saturation magnetization magnetic layer has saturation magnetization Ms.sup.high which, when saturation magnetization of the free layer is Ms.sup.free and saturation magnetization of the hard magnetic layer is Ms.sup.hard, satisfies at least one of Ms.sup.high .gtoreq.Ms.sup.free or Ms.sup.high .gtoreq.Ms.sup.hard. In a spin valve GMR head of a reversed structure or a dual element type, even when a track width is narrowed, occurrence of Barkhausen noise can be effectively suppressed.
    Type: Grant
    Filed: April 29, 1998
    Date of Patent: September 12, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Hitoshi Iwasaki
  • Patent number: 6111729
    Abstract: A magnetoresistance effect element provided with a spin valve film composed of a first magnetic layer formed on a metallic buffer layer, a middle non-magnetic layer formed on the first magnetic layer, and a second magnetic layer formed on the non-magnetic layer, has an atomic-diffusion barrier layer whose average thickness is 2 nm or less formed in the interface between the metallic buffer layer and the first magnetic layer. Or a magnetoresistance effect element provided with a spin valve film composed of a first magnetic layer composed of a laminated film of a magnetic undercoat layer and a ferromagnetic layer, a middle non-magnetic layer formed on the first magnetic layer, and a second magnetic layer formed on the middle non-magnetic layer, has an atomic-diffusion barrier layer whose average thickness is 2 nm or less formed in the interface between the magnetic undercoat layer and the ferromagnetic layer.
    Type: Grant
    Filed: May 18, 1999
    Date of Patent: August 29, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuzo Kamiguchi, Akiko Saito, Kazuhiro Saito, Hideaki Fukuzawa, Hitoshi Iwasaki, Masashi Sahashi