Patents by Inventor Hisateru Sato

Hisateru Sato 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: 6689495
    Abstract: A magnetic recording medium is constructed to include at least one exchange layer structure and a magnetic layer provided on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer. At least one of the ferromagnetic layer and the magnetic layer has a granular layer structure in which ferromagnetic crystal grains are uniformly distributed within a non-magnetic base material.
    Type: Grant
    Filed: June 6, 2000
    Date of Patent: February 10, 2004
    Assignee: Fujitsu Limited
    Inventors: Hisateru Sato, Isatake Kaitsu, E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita
  • Patent number: 6562481
    Abstract: A magnetic storage medium has a non-magnetic substrate and a recording layer. The recording layer comprises a non-magnetic matrix and crystal grains consisting of a ferromagnetic material. Each of the crystal grains dispersed in the recording layer is a columnar shaped grain which penetrates a suface of the recording layer and has height of 30 nm or less, and a mean value of grain sizes of the crystal grains in an internal direction of the recording layer is 15 nm or less. (Ku·V)/(kB·T) is not less than 60. A mean value Hk of anisotropic magnetic fields of the plurality of crystal grains is 20 kOe or less.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: May 13, 2003
    Assignee: Fujitsu Limited
    Inventors: Isatake Kaitsu, Hisateru Sato, Iwao Okamoto
  • Publication number: 20030082410
    Abstract: A magnetic recording medium is constructed to include at least one exchange layer structure and a magnetic layer provided on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer. At least one of the ferromagnetic layer and the magnetic layer has a granular layer structure in which ferromagnetic crystal grains are uniformly distributed within a non-magnetic base material.
    Type: Application
    Filed: December 2, 2002
    Publication date: May 1, 2003
    Applicant: Fujitsu Limited
    Inventors: Hisateru Sato, Isatake Kaitsu, E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita
  • Patent number: 6534205
    Abstract: There is provided a magnetic storage medium capable of recording information at high recording density and also to regenerating the information with a high quality of signal (high S/Nm), and in addition contributing to the elongation of a life span of the recorded information. The magnetic storage medium comprises a non-magnetic substrate and a magnetic recording layer provided on the substrate. The magnetic recording layer has a ferromagnetic grain consisting of a ferromagnetic material and an antiferromagnetic matrix consisting of an antiferromagnetic material.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: March 18, 2003
    Assignee: Fujitsu Limited
    Inventors: Hisateru Sato, Isatake Kaitsu, Iwao Okamoto
  • Publication number: 20020064685
    Abstract: There is provided a magnetic storage medium capable of recording information at high recording density and also to regenerating the information with a high quality of signal (high S/Nm), and in addition contributing to the elongation of a life span of the recorded information. The magnetic storage medium comprises a non-magnetic substrate and a magnetic recording layer provided on the substrate. The magnetic recording layer has a ferromagnetic grain consisting of a ferromagnetic material and an antiferromagnetic matrix consisting of an antiferromagnetic material.
    Type: Application
    Filed: September 30, 1999
    Publication date: May 30, 2002
    Inventors: HISATERU SATO, ISATAKE KAITSU, IWAO OKAMOTO
  • Publication number: 20010012573
    Abstract: A magnetic recording medium is provided which has ferromagnetic crystal grains having a uniform grain size which are successfully separated from each other. The magnetic recording medium comprises a non-magnetic substrate 1 and a recording layer 2 formed thereon, wherein the recording layer consists of at least one non-ferromagnetic material selected from the group consisting of non-magnetic materials and antiferromagnetic materials and a plurality of crystal grains 2—1 made of ferromagnetic material solid-insoluble with the non-ferromagnetic material which are dispersed in the non-ferromagnetic material. The recording layer has at least two phases, along the depth direction, with each phase having a different mean composition ratio of the ferromagnetic material to the non-ferromagnetic material from that or those of the adjacent phase or phases.
    Type: Application
    Filed: December 8, 2000
    Publication date: August 9, 2001
    Applicant: FUJITSU LIMITED
    Inventors: Isatake Kaitsu, Hisateru Sato, Iwao Okamoto