Patents by Inventor Izuru Ishii

Izuru Ishii 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: 7675715
    Abstract: In one embodiment, a seed layer, an underlayer, and a magnetic domain control layer are laminated on both sides of a magnetoresistive sheet unit. A lower electrode film is thinly formed on an upper portion of the magnetic domain control film. A portion of the lower electrode film near the magnetoresistive sheet unit does not protrude substantially from an upper surface of the magnetoresistive sheet unit. Should the portion protrude, a step from the upper surface of the magnetoresistive sheet unit is about 14 nm or less. This portion and the upper surface of the magnetoresistive sheet unit are formed into a flat surface. An upper electrode film is formed thickly on an upper portion of the lower electrode film on an outside thereof so as to circumvent the flat surface. A protective layer, an upper gap film, and an upper magnetic shield film are also formed.
    Type: Grant
    Filed: September 14, 2005
    Date of Patent: March 9, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masatoshi Arasawa, Izuru Ishii, Shuichi Kojima, Naoki Koyama, Norihiro Ookawa
  • Patent number: 7586715
    Abstract: Even if the track and gap widths are made narrow in a read head, a narrow track head has so far been unable to afford satisfactory off-track characteristics because of a wide shield spacing over electrodes. The invention provides a magnetic head wherein, in the height direction of a magnetoresistive element, the spacing between an upper magnetic shield and a lower magnetic shield at an air bearing surface is narrower than the spacing between the upper and lower magnetic shields formed over a thickest portion of each of electrodes in contact with associated magnetic domain control layers.
    Type: Grant
    Filed: January 20, 2006
    Date of Patent: September 8, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Naoki Koyama, Kouji Okazaki, Izuru Ishii, Shuichi Kojima, Shigeru Tadokoro
  • Publication number: 20060158789
    Abstract: Even if the track and gap widths are made narrow in a read head, a narrow track head has so far been unable to afford satisfactory off-track characteristics because of a wide shield spacing over electrodes. The invention provides a magnetic head wherein, in the height direction of a magnetoresistive element, the spacing between an upper magnetic shield and a lower magnetic shield at an air bearing surface is narrower than the spacing between the upper and lower magnetic shields formed over a thickest portion of each of electrodes in contact with associated magnetic domain control layers.
    Type: Application
    Filed: January 20, 2006
    Publication date: July 20, 2006
    Applicant: Hitachi Global Storage Technologies
    Inventors: Naoki Koyama, Kouji Okazaki, Izuru Ishii, Shuichi Kojima, Shigeru Tadokoro
  • Publication number: 20060056112
    Abstract: Making a geometric track width small does not decrease a read track width, resulting only in an output being reduced. In one embodiment, a seed layer, an underlayer, and a magnetic domain control layer are laminated on both sides of a magnetoresistive sheet unit. A lower electrode film is thinly formed on an upper portion of the magnetic domain control film. A portion of the lower electrode film near the magnetoresistive sheet unit does not protrude substantially from an upper surface of the magnetoresistive sheet unit. Should the portion protrude, a step from the upper surface of the magnetoresistive sheet unit is about 14 nm or less. This portion and the upper surface of the magnetoresistive sheet unit are formed into a flat surface. An upper electrode film is formed thickly on an upper portion of the lower electrode film on an outside thereof so as to circumvent the flat surface. A protective layer, an upper gap film, and an upper magnetic shield film are also formed.
    Type: Application
    Filed: September 14, 2005
    Publication date: March 16, 2006
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masatoshi Arasawa, Izuru Ishii, Shuichi Kojima, Naoki Koyama, Norihiro Ookawa
  • Patent number: 6424508
    Abstract: A tunnel junction MR head can be easily manufactured and arranged as follow. A first tunnel junction is formed by a magnetization free layer, a first magnetization pinned layer and a thin insulated layer formed between the both layers. A second tunnel junction is formed by the magnetization free layer, a second magnetization pinned layer and an insulated layer. The first and second tunnel junctions are connected to both ends of the magnetization free layer through the magnetization free layer. A detection current flowing from a first electrode connected to the first tunnel junction is passed to a second electrode through the first tunnel junction, the magnetization free layer and the second tunnel junction.
    Type: Grant
    Filed: August 26, 1999
    Date of Patent: July 23, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Shigeru Tadokoro, Izuru Ishii