Patents by Inventor Masayasu Kagawa

Masayasu Kagawa 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: 7274541
    Abstract: In formation of an upper shield of a magnetic thin film head by electroplating, a current density of electroplating is regulated stepwise with time. Thus, in the upper shield formation, a film composition and magnetic characteristic with respect to the direction of film thickness can be controlled precisely, making it possible to provide a magnetic thin film head featuring significantly reduced noise-after-write and output fluctuation.
    Type: Grant
    Filed: April 1, 2005
    Date of Patent: September 25, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Gen Oikawa, Shuichi Kojima, Harunobu Saito, Noriyuki Saiki, Masayasu Kagawa, Akira Kondo, Kenji Ishikake, Hiromi Shiina
  • Publication number: 20070079498
    Abstract: Multiple thin films of spin-valve GMR sensor are formed in a trapezoidal cross-sectional shape by laminating an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer and a nonmagnetic protective layer on a lower insulated gap layer. The amount of etching of the lower insulated gap layer produced in the process of patterning the spin-valve giant magnetoresistive layers into the multiple thin films of spin-valve GMR sensor is 10 nm or less. Further, the angle ? which the tangent line of each side face of the multiple thin films to the middle line of the free magnetic layer in its thickness direction forms with respect to the middle line of the free magnetic layer becomes 45 degrees or more. This structure makes it possible to provide such a spin-valve giant magnetoresistive head that it meets the requirements for securing constant breakdown voltage and preventing instability of MR output voltage waveform.
    Type: Application
    Filed: December 11, 2006
    Publication date: April 12, 2007
    Inventors: Masatoshi Arasawa, Haruko Tanaka, Makoto Morijiri, Koichi Nishioka, Shuichi Kojima, Masayasu Kagawa
  • Patent number: 7159304
    Abstract: Multiple thin films of spin-valve GMR sensor are formed in a trapezoidal cross-sectional shape by laminating an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer and a nonmagnetic protective layer on a lower insulated gap layer. The amount of etching of the lower insulated gap layer produced in the process of patterning the spin-valve giant magnetoresistive layers into the multiple thin films of spin-valve GMR sensor is 10 nm or less. Further, the angle ? which the tangent line of each side face of the multiple thin films to the middle line of the free magnetic layer in its thickness direction forms with respect to the middle line of the free magnetic layer becomes 45 degrees or more. This structure makes it possible to provide such a spin-valve giant magnetoresistive head that it meets the requirements for securing constant breakdown voltage and preventing instability of MR output voltage waveform.
    Type: Grant
    Filed: February 17, 2004
    Date of Patent: January 9, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Masatoshi Arasawa, Haruko Tanaka, Makoto Morijiri, Koichi Nishioka, Shuichi Kojima, Masayasu Kagawa
  • Publication number: 20050168876
    Abstract: In formation of an upper shield of a magnetic thin film head by electroplating, a current density of electroplating is regulated stepwise with time. Thus, in the upper shield formation, a film composition and magnetic characteristic with respect to the direction of film thickness can be controlled precisely, making it possible to provide a magnetic thin film head featuring significantly reduced noise-after-write and output fluctuation.
    Type: Application
    Filed: April 1, 2005
    Publication date: August 4, 2005
    Inventors: Gen Oikawa, Shuichi Kojima, Harunobu Saito, Noriyuki Saiki, Masayasu Kagawa, Akira Kondo, Kenji Ishikake, Hiromi Shiina
  • Publication number: 20040158973
    Abstract: Multiple thin films of spin-valve GMR sensor are formed in a trapezoidal cross-sectional shape by laminating an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer and a nonmagnetic protective layer on a lower insulated gap layer. The amount of etching of the lower insulated gap layer produced in the process of patterning the spin-valve giant magnetoresistive layers into the multiple thin films of spin-valve GMR sensor is 10 nm or less. Further, the angle &thgr; which the tangent line of each side face of the multiple thin films to the middle line of the free magnetic layer in its thickness direction forms with respect to the middle line of the free magnetic layer becomes 45 degrees or more. This structure makes it possible to provide such a spin-valve giant magnetoresistive head that it meets the requirements for securing constant breakdown voltage and preventing instability of MR output voltage waveform.
    Type: Application
    Filed: February 17, 2004
    Publication date: August 19, 2004
    Inventors: Masatoshi Arasawa, Haruko Tanaka, Makoto Morijiri, Koichi Nishioka, Shuichi Kojima, Masayasu Kagawa
  • Patent number: 6717778
    Abstract: Multiple thin films of spin-valve GMR sensor are formed in a trapezoidal cross-sectional shape by laminating an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer and a nonmagnetic protective layer on a lower insulated gap layer. The amount of etching of the lower insulated gap layer produced in the process of patterning the spin-valve giant magnetoresistive layers into the multiple thin films of spin-valve GMR sensor is 10 nm or less. Further, the angle &thgr; which the tangent line of each side face of the multiple thin films to the middle line of the free magnetic layer in its thickness direction forms with respect to the middle line of the free magnetic layer becomes 45 degrees or more. This structure makes it possible to provide such a spin-valve giant magnetoresistive head that it meets the requirements for securing constant breakdown voltage and preventing instability of MR output voltage waveform.
    Type: Grant
    Filed: August 17, 2001
    Date of Patent: April 6, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Masatoshi Arasawa, Haruko Tanaka, Makoto Morijiri, Koichi Nishioka, Shuichi Kojima, Masayasu Kagawa
  • Publication number: 20020064005
    Abstract: Multiple thin films of spin-valve GMR sensor are formed in a trapezoidal cross-sectional shape by laminating an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer and a nonmagnetic protective layer on a lower insulated gap layer. The amount of etching of the lower insulated gap layer produced in the process of patterning the spin-valve giant magnetoresistive layers into the multiple thin films of spin-valve GMR sensor is 10 nm or less. Further, the angle &thgr; which the tangent line of each side face of the multiple thin films to the middle line of the free magnetic layer in its thickness direction forms with respect to the middle line of the free magnetic layer becomes 45 degrees or more. This structure makes it possible to provide such a spin-valve giant magnetoresistive head that it meets the requirements for securing constant breakdown voltage and preventing instability of MR output voltage waveform.
    Type: Application
    Filed: August 17, 2001
    Publication date: May 30, 2002
    Inventors: Masatoshi Arasawa, Haruko Tanaka, Makoto Morijiri, Koichi Nishioka, Shuichi Kojima, Masayasu Kagawa
  • Publication number: 20010036043
    Abstract: In formation of an upper shield of a magnetic thin film head by electroplating, a current density of electroplating is regulated stepwise with time. Thus, in the upper shield formation, a film composition and magnetic characteristic with respect to the direction of film thickness can be controlled precisely, making it possible to provide a magnetic thin film head featuring significantly reduced noise-after-write and output fluctuation.
    Type: Application
    Filed: February 16, 2001
    Publication date: November 1, 2001
    Inventors: Gen Oikawa, Shuichi Kojima, Harunobu Saito, Noriyuki Saiki, Masayasu Kagawa, Akira Kondo, Kenji Ishikake, Hiromi Shiina