Patents by Inventor Masafumi Nakada

Masafumi Nakada 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: 6934132
    Abstract: A magneto-resistance effect head is provided with a lower conductive layer which is provided with a recessed portion, and a vertical bias layer is provided in the recessed portion. A free layer is provided on the lower conductive layer. On the free layer, layered in the following order are the non-magnetic layer, the fixed layer, the fixing layer, and the upper layer so as not to be placed inmediately above the vertical bias layer. The non-magnetic layer, the fixed layer, the fixing layer, and the upper layer are buried in an insulation layer. Furthermore, an upper conductive layer is provided on the upper layer and the insulation layer. In the direction of the magnetic field applied by the vertical bias layer, the free layer is made greater in length than the fixed layer and the free layer is disposed in proximity to the vertical bias layer with the distance between the fixed layer and the vertical bias layer remaining unchanged.
    Type: Grant
    Filed: July 30, 2001
    Date of Patent: August 23, 2005
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kiyokazu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata
  • Publication number: 20050147343
    Abstract: An optical element is formed from a molded body which is formed using an impact consolidation phenomenon in which a mechanical impact is applied to ultra fine fragile particles which are supplied onto a substrate so that the ultra fine fragile particles are pulverized and bonded to each other In the optical element, d6/?4<4×10?5 nm2 holds, in which d (nm) represents the average radius of a part of the molded body, such as a pore (void) or a different phase, having a refractive index different from that of a primary component of the molded body, and in which ? (nm) represents the wavelength of light transmitting through the molded body.
    Type: Application
    Filed: November 26, 2004
    Publication date: July 7, 2005
    Inventors: Masafumi Nakada, Keishi Ohashi, Jun Akedo
  • Patent number: 6903908
    Abstract: A magnetoresistive effect sensor uses a shielded-type magnetoresistive effect element using a magnetoresistive effect film formed by a basic configuration of a combination of a free layer, a barrier layer formed on the free layer, and a fixed layer formed on the barrier layer, wherein a sensing current flows substantially perpendicular to the magnetoresistive effect film, and wherein an amorphous material or a microcrystalline material is used in a lower shield.
    Type: Grant
    Filed: May 14, 2001
    Date of Patent: June 7, 2005
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjo, Junichi Fujikata, Kunihiko Ishihara, Shigeru Mori
  • Patent number: 6798626
    Abstract: A magnetoresistive effect element which is easy to manufacture and in which a sense current is prevented from bypassing a barrier layer is provided. Also provided are a method for manufacturing the element and a magnetic recording apparatus utilizing the element. This magnetoresistive effect element utilizes an MTJ film which comprises, for forming its basic structure, a free layer, a barrier layer, a pinned layer and a pinning layer, wherein an oxide or a nitride layer is formed by oxidizing or nitriding metallic materials constituting the pinned layer and pinning layer.
    Type: Grant
    Filed: February 3, 2003
    Date of Patent: September 28, 2004
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjou, Shinsaku Saitoh
  • Publication number: 20040174641
    Abstract: A magneto-resistance effect head is provided with a lower conductive layer which is provided with a recessed portion, and a vertical bias layer is provided in the recessed portion. A free layer is provided on the lower conductive layer. On the free layer, layered in the following order are the non-magnetic layer, the fixed layer, the fixing layer, and the upper layer so as not to be placed immediately above the vertical bias layer. The non-magnetic layer, the fixed layer, the fixing layer, and the upper layer are buried in an insulation layer. Furthermore, an upper conductive layer is provided on the upper layer and the insulation layer. In the direction of the magnetic field applied by the vertical bias layer, the free layer is made greater in length than the fixed layer and the free layer is disposed in proximity to the vertical bias layer with the distance between the fixed layer and the vertical bias layer remaining unchanged.
    Type: Application
    Filed: March 18, 2004
    Publication date: September 9, 2004
    Inventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kiyokasu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata
  • Patent number: 6781800
    Abstract: A magnetic layer which is exchange-coupled to an antiferromagnetic layer and given an exchange bias therefrom is laminated via a non-magnetic layer on another magnetic layer to form an MR film. The antiferromagnetic layer (PtMn, PdMn or NiMn) is laminated on a ground layer (Zr, Hf, Zr—Hf, Zr—Co, Zr—Au, Ni—O, Co—O or Fe—O) so that the antiferromagnetic layer has a surface of an average roughness of 1-5 Å. A conduction layer is formed adjacent to the magnetic layer for sensing a magnetic field. The conduction layer is made of Cu, Ag, Au or an alloy composed of two selected therefrom. A layer made of Zr, Ta, Zr—O, Ta—O or a mixture thereof is laminated on the conduction layer. The MR film exhibits a large resistance variation linearly at near zero magnetic field with an excellent thermal stability.
    Type: Grant
    Filed: April 8, 2003
    Date of Patent: August 24, 2004
    Assignee: TDK Corporation
    Inventors: Junichi Fujikata, Masafumi Nakada
  • Patent number: 6775110
    Abstract: A magnetoresistance effect device has the basic structure of substrate/sublayer/NiFe layer/CoFe layer/non-magnetic layer/fixed magnetic layer/antiferromagnetic layer. The sublayer may be Ta at a film thickness of not less than 0.2 nm but less than 3.0 nm, or Hf at a film thickness of not less than 0.2 nm but not greater than 1.5 nm, or Zr at a film thickness of not less than 0.2 nm but not greater than 2.5 nm. It is permissible to use only an NiFe layer instead of the NiFe layer/CoFe layer.
    Type: Grant
    Filed: May 12, 1998
    Date of Patent: August 10, 2004
    Assignee: TDK Corporation
    Inventors: Kazuhiko Hayashi, Shigeru Mori, Masafumi Nakada
  • Publication number: 20040134877
    Abstract: In a magnetoresistance apparatus including a first functional layer and a second functional layer magnetically connected to the first functional layer, an overlapping ratio of the second functional layer onto the first functional layer is approximately 0 to 10 percent.
    Type: Application
    Filed: January 5, 2004
    Publication date: July 15, 2004
    Applicant: TDK CORPORATION
    Inventors: Nobuyuki Ishiwata, Shigeru Mori, Kiyokazu Nagahara, Tsutomu Ishi, Kunihiko Ishihara, Eizo Fukami, Masafumi Nakada
  • Publication number: 20040131001
    Abstract: An optical element structure allowing an increased power density of aperture-transmitted light while suppressing increase in temperature is disclosed. A conductive film has a sub-wavelength aperture formed therein and a periodic surface topography formed thereon. A lens focuses light onto the periodic surface topography with a predetermined diameter. The predetermined diameter of incident light on the conductive film and a period of the periodic surface topography are determined so that a power ratio of aperture-transmitted light to the light beam is greater than that of aperture-transmitted light which would be obtained if no periodic surface topography is provided in the conductive film.
    Type: Application
    Filed: January 6, 2003
    Publication date: July 8, 2004
    Applicant: NEC CORPORATION
    Inventors: Masafumi Nakada, Tineke Thio
  • Patent number: 6747853
    Abstract: A magneto-resistance effect head is provided with a lower conductive layer which is provided with a recessed portion, and a vertical bias layer is provided in the recessed portion. A free layer is provided on the lower conductive layer. On the free layer, layered in the following order are the non-magnetic layer, the fixed layer, the fixing layer, and the upper layer so as not to be placed immediately above the vertical bias layer. The non-magnetic layer, the fixed layer, the fixing layer, and the upper layer are buried in an insulation layer. Furthermore, an upper conductive layer is provided on the upper layer and the insulation layer. In the direction of the magnetic field applied by the vertical bias layer, the free layer is made greater in length than the fixed layer and the free layer is disposed in proximity to the vertical bias layer with the distance between the fixed layer and the vertical bias layer remaining unchanged.
    Type: Grant
    Filed: May 21, 2003
    Date of Patent: June 8, 2004
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kiyokazu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata
  • Patent number: 6718621
    Abstract: In a production process of an MR head using the tunnel junction film basically consisting of a free layer, a barrier layer, and a pinned layer, the resistance between the free layer and the pined layer reduced beforehand and increased afterward up to a resistance value necessary when actually used. While the resistance between the free layer and the pinned layer is low, current can easily flow, suppressing charge up, thus preventing insulation destruction of the barrier layer. This significantly increases a production yield of a recording/reproduction head using a ferromagnetic tunnel junction element.
    Type: Grant
    Filed: May 9, 2000
    Date of Patent: April 13, 2004
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjo, Shinsaku Saitoh
  • Patent number: 6639766
    Abstract: A magneto-resistance effect (“MR”) type composite head includes a reproduction head with an MR element arranged between a first and a second magnetic shield; and a recording head arranged adjacent to the reproduction head so as to use the second magnetic shield as a first magnetic pole film and having a second magnetic pole film opposing to the first magnetic pole via a magnetic gap; the MR element includes a center region including a ferromagnetic tunnel junction magneto-resistance effect film having a first ferromagnetic layer and a second ferromagnetic layer for generating a magneto-resistance effect using the first and the second magnetic shields as electrodes so that a current flows in an almost vertical direction between the first and the second magnetic shields; a tunnel barrier layer provided between the first and the second ferromagnetic layer; and an end region arranged to sandwich the center region from both sides for /applying a bias magnetic field to the center region.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: October 28, 2003
    Assignee: NEC Corporation
    Inventors: Ishiwata Nobuyuki, Hisanao Tsuge, Hisao Matsutera, Yuji Tsukamoto, Masafumi Nakada, Atsushi Kamijo
  • Publication number: 20030193762
    Abstract: A magneto-resistance effect head is provided with a lower conductive layer which is provided with a recessed portion, and a vertical bias layer is provided in the recessed portion. A free layer is provided on the lower conductive layer. On the free layer, layered in the following order are the non-magnetic layer, the fixed layer, the fixing layer, and the upper layer so as not to be placed immediately above the vertical bias layer. The non-magnetic layer, the fixed layer, the fixing layer, and the upper layer are buried in an insulation layer. Furthermore, an upper conductive layer is provided on the upper layer and the insulation layer. In the direction of the magnetic field applied by the vertical bias layer, the free layer is made greater in length than the fixed layer and the free layer is disposed in proximity to the vertical bias layer with the distance between the fixed layer and the vertical bias layer remaining unchanged.
    Type: Application
    Filed: May 21, 2003
    Publication date: October 16, 2003
    Inventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kiyokazu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata
  • Patent number: 6624987
    Abstract: A magnetoresistive effect head which is easy to manufacture and in which a sense current is prevented from bypassing a barrier layer is provided. Also provided are a method for manufacturing the head and a magnetic recording apparatus utilizing the head. This magnetoresistive effect head utilizes an MTJ film which comprises, for forming its basic structure, a free layer, a barrier layer, a pinned layer and a pinning layer, wherein an oxide or a nitride layer is formed by oxidizing or nitriding metallic materials constituting the pinned layer and pinning layer.
    Type: Grant
    Filed: May 31, 2000
    Date of Patent: September 23, 2003
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjou, Shinsaku Saitoh
  • Publication number: 20030169543
    Abstract: A magnetic layer which is exchange-coupled to an antiferromagnetic layer and given an exchange bias therefrom is laminated via a non-magnetic layer on another magnetic layer to form an MR film. The antiferromagnetic layer (PtMn, PdMn or NiMn) is laminated on a ground layer (Zr, Hf, Zr—Hf, Zr—Co, Zr—Au, Ni—O, Co—O or Fe—O) so that the antiferromagnetic layer has a surface of an average roughness of 1-5 Å. A conduction layer is formed adjacent to the magnetic layer for sensing a magnetic field. The conduction layer is made of Cu, Ag, Au or an alloy composed of two selected therefrom. A layer made of Zr, Ta, Zr—O, Ta—O or a mixture thereof is laminated on the conduction layer. The MR film exhibits a large resistance variation linearly at near zero magnetic field with an excellent thermal stability.
    Type: Application
    Filed: April 8, 2003
    Publication date: September 11, 2003
    Inventors: Junichi Fujikata, Masafumi Nakada
  • Publication number: 20030151859
    Abstract: A magnetoresistive effect element which is easy to manufacture and in which a sense current is prevented from bypassing a barrier layer is provided. Also provided are a method for manufacturing the element and a magnetic recording apparatus utilizing the element. This magnetoresistive effect element utilizes an MTJ film which comprises, for forming its basic structure, a free layer, a barrier layer, a pinned layer and a pinning layer, wherein an oxide or a nitride layer is formed by oxidizing or nitriding metallic materials constituting the pinned layer and pinning layer.
    Type: Application
    Filed: February 3, 2003
    Publication date: August 14, 2003
    Applicant: NEC CORPORATION
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjou, Shinsaku Saitoh
  • Patent number: 6570744
    Abstract: A magnetic layer which is exchange-coupled to an antiferromagnetic layer and given an exchange bias therefrom is laminated via a non-magnetic layer on another magnetic layer to form an MR film. The antiferromagnetic layer (PtMn, PdMn or NiMn) is laminated on a ground layer(Zr, Hf, Zr—Hf, Zr—Co, Zr—Au, Ni—O, Co—O or Fe—O) so that the antiferromagnetic layer has a surface of an average roughness of 1-5 Å. A conduction layer is formed adjacent to the magnetic layer for sensing a magnetic field. The conduction layer is made of Cu, Ag, Au or an alloy composed of two selected therefrom. A layer made of Zr, Ta, Zr—O, Ta—O or a mixture thereof is laminated on the conduction layer. The MR film exhibits a large resistance variation linearly at near zero magnetic field with an excellent thermal stability.
    Type: Grant
    Filed: May 25, 2000
    Date of Patent: May 27, 2003
    Assignee: TDK Corporation
    Inventors: Junichi Fujikata, Masafumi Nakada
  • Patent number: 6542342
    Abstract: In a magnetoresistive effect transducer including a pinning layer, a pinned layer, a free layer and a non-magnetic layer inserted between the pinned layer and the free layer, a longitudinal bias layer is connected directly to a part of the free layer to apply a bias magnetic field to the free layer, thus biasing a magnetization direction of the free layer so that the magnetization direction of the free layer coincides with that of the longitudinal bias layer.
    Type: Grant
    Filed: November 29, 1999
    Date of Patent: April 1, 2003
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Tsutomu Ishi, Hiroaki Honjou, Kunihiko Ishihara, Jun-Ichi Fujikata, Hisao Matsutera, Hisanao Tsuge, Atsushi Kamijo
  • Patent number: 6538861
    Abstract: A magnetoresistive head whose operation depends on a magnetoresistive effect is configured using a ferromagnetic tunnel junction (MTJ) film, which is arranged between a lower electrode and an upper electrode. The ferromagnetic tunnel junction film is basically configured using a set of a free layer, a barrier layer and a fixing layer, which are sequentially formed and laminated on the lower electrode. Herein, the ferromagnetic tunnel junction film is designed to avoid electrostatic destruction in manufacture by prescribed measures. For example, the barrier layer is reduced in thickness at a terminal portion as compared with a center portion. Or, the barrier layer has a defect at the terminal portion. In addition, it is possible to provide a conductor in connection with the barrier layer in proximity to its terminal portion.
    Type: Grant
    Filed: June 19, 2000
    Date of Patent: March 25, 2003
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjou, Kunihiko Ishihara, Tamaki Toba, Hisanao Tsuge, Atsushi Kamijo
  • Publication number: 20030035256
    Abstract: In a magnetoresistive effect transducer including a pinning layer, a pinned layer, a free layer and a non-magnetic layer inserted between the pinned layer and the free layer, a longitudinal bias layer is connected directly to a part of the free layer to apply a bias magnetic field to the free layer, thus biasing a magnetization direction of the free layer so that the magnetization direction of the free layer coincides with that of the longitudinal bias layer.
    Type: Application
    Filed: September 12, 2002
    Publication date: February 20, 2003
    Applicant: NEC Corporation
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Tsutomu Ishi, Hiroaki Honjou, Kunihiko Ishihara, Jun-Ichi Fujikata, Hisao Matsutera, Hisanao Tsuge, Atsushi Kamijo