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).

  • Patent number: 7223485
    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: Grant
    Filed: March 7, 2005
    Date of Patent: May 29, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Yuzo Kamiguchi, Hitoshi Iwasaki, Masashi Sahashi
  • Patent number: 7116527
    Abstract: A base film of a hard magnetic film containing Co as a structural element has a crystal metal base film such as a Cr film formed on the main surface of a substrate and a reactive base film (mixing layer) formed between the substrate and the crystal metal base film and having a reactive amorphous layer containing a structural element of the substrate and a structural element of the crystal metal base film. A hard magnetic film containing Co as a structural element is formed on the crystal metal base film. With the crystal metal base film such as the Cr film formed on an amorphous layer, a hard magnetic film with a bi-crystal structure can be obtained with high reproducibility. With the hard magnetic film, magnetic characteristics such as coercive force Hc, residual magnetization Mr, saturated magnetization Ms, and square ratio S can be improved without need to use a thick base film.
    Type: Grant
    Filed: September 29, 1997
    Date of Patent: October 3, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Shin-ichi Nakamura, Yuzo Kamiguchi, Hitoshi Iwasaki, Akio Hori, Susumu Hashimoto
  • Publication number: 20060198063
    Abstract: A base film of a hard magnetic film containing Co as a structural element has a crystal metal base film such as a Cr film formed on the main surface of a substrate and a reactive base film (mixing layer) formed between the substrate and the crystal metal base film and having a reactive amorphous layer containing a structural element of the substrate and a structural element of the crystal metal base film. A hard magnetic film containing Co as a structural element is formed on the crystal metal base film. With the crystal metal base film such as the Cr film formed on an amorphous layer, a hard magnetic film with a bi-crystal structure can be obtained with high reproducibility. With the hard magnetic film, magnetic characteristics such as coercive force Hc, residual magnetization Mr, saturated magnetization Ms, and square ratio S can be improved without need to use a thick base film.
    Type: Application
    Filed: May 4, 2006
    Publication date: September 7, 2006
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Shin-ichi Nakamura, Yuzo Kamiguchi, Hitoshi Iwasaki, Akio Hori, Susumu Hashimoto
  • 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: 7072152
    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: Grant
    Filed: March 14, 2005
    Date of Patent: July 4, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Hiroaki Yoda, Yuzo Kamiguchi, Tomohiko Nagata
  • 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
  • Publication number: 20060126230
    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: February 6, 2006
    Publication date: June 15, 2006
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiromi Yuasa, Hiroaki Yoda, Yuzo Kamiguchi, Tomohiko Nagata
  • 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
  • Patent number: 7027273
    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. The intermediate layer includes a stacked film of a metal layer/an oxide layer, a stacked film of a metal layer/a nitride layer, a sandwich film of a metal layer/an oxide layer/a metal layer, or a sandwich film of a metal layer/a nitride layer/a metal layer.
    Type: Grant
    Filed: October 21, 2004
    Date of Patent: April 11, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Yuzo Kamiguchi, Hiromi Yuasa
  • Publication number: 20060071287
    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: November 22, 2005
    Publication date: April 6, 2006
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
  • Patent number: 7016162
    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: Grant
    Filed: October 19, 2004
    Date of Patent: March 21, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Hiroaki Yoda, Yuzo Kamiguchi, Tomohiko Nagata
  • Patent number: 7016169
    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, a first electrode, a second electrode, a pair of first antiferromagnetic films, and a pair of second antiferromagnetic films. The first electrode is connected with the underlayer and the second electrode is connected with the protective layer, the electrodes allowing a current to flow in a direction substantially perpendicular to the plane of the magnetoresistive film. The pair of first antiferromagnetic films imparts a magnetic bias to the first magnetization free layer in a predetermined direction, and the pair of second antiferromagnetic films imparts a magnetic bias to the second magnetization free layer in a predetermined direction.
    Type: Grant
    Filed: October 21, 2004
    Date of Patent: March 21, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Yuzo Kamiguchi, Hiromi Yuasa
  • Patent number: 7008702
    Abstract: A magnetoresistance effect element includes a nonmagnetic spacer layer, first and second ferromagnetic layer separated by the nonmagnetic spacer layer, and a nonmagnetic conductivity layer. The first ferromagnetic layer has a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field. The second ferromagnetic layer has first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films. The magnetization of the first ferromagnetic layer freely rotates in a magnetic field signal. The nonmagnetic conductivity layer is disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic high-conductivity layer and the nonmagnetic spacer layer. The first ferromagnetic layer has a film thickness between 0.5 nanometers and 4.5 nanometers.
    Type: Grant
    Filed: October 10, 2001
    Date of Patent: March 7, 2006
    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: 6937447
    Abstract: A magnetoresistance effect element includes a first ferromagnetic layer, insulating layer overlying the first ferromagnetic layer, and second ferromagnetic layer overlying the insulating layer. The insulating layer has formed a through hole having an opening width not larger than 20 nm, and the first and second ferromagnetic layers are connected to each other via the through hole.
    Type: Grant
    Filed: September 17, 2002
    Date of Patent: August 30, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shiho Okuno, Yuichi Ohsawa, Shigeru Haneda, Yuzo Kamiguchi, Tatsuya Kishi
  • Publication number: 20050167770
    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: March 15, 2005
    Publication date: August 4, 2005
    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: 20050152077
    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: March 7, 2005
    Publication date: July 14, 2005
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Yuzo Kamiguchi, Hitoshi Iwasaki, Masashi Sahashi
  • Publication number: 20050152074
    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: March 14, 2005
    Publication date: July 14, 2005
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiromi Yuasa, Hiroaki Yoda, Yuzo Kamiguchi, Tomohiko Nagata
  • Patent number: 6914757
    Abstract: A magnetoresistance effect element includes a magnetization fixed layer in which the direction of magnetization is substantially fixed to one direction, a magnetization free layer in which the direction of magnetization varies in response to an external magnetic field, and a non-magnetic intermediate layer formed between the magnetization fixed layer and the magnetization free layer. The magnetoresistance effect element has a resistance varying in response to a relative angle between the direction of magnetization in the magnetization fixed layer and the direction of magnetization in the magnetization free layer, the resistance being detected when a sense current is applied to the film planes of the magnetization fixed layer, the non-magnetic intermediate layer, and the magnetization free layer in a direction substantially perpendicular thereto.
    Type: Grant
    Filed: September 24, 2001
    Date of Patent: July 5, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Hiroaki Yoda, Yuzo Kamiguchi, Tomohiko Nagata
  • Patent number: 6905780
    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: Grant
    Filed: February 1, 2002
    Date of Patent: June 14, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Yuzo Kamiguchi, Hitoshi Iwasaki, Masashi Sahashi
  • Publication number: 20050094327
    Abstract: A magnetoresistance effect element includes a first ferromagnetic layer (1), insulating layer (3) overlying the first ferromagnetic layer, and second ferromagnetic layer (2) overlying the insulating layer. The insulating layer has formed a through hole (A) having an opening width not larger than 20 nm, and the first and second ferromagnetic layers are connected to each other via the through hole.
    Type: Application
    Filed: December 8, 2004
    Publication date: May 5, 2005
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shiho Okuno, Yuichi Ohsawa, Shigeru Haneda, Yuzo Kamiguchi, Tatsuya Kishi