Patents by Inventor Satoru Yoshimura

Satoru Yoshimura 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: 6709775
    Abstract: A magnetic recording medium capable of suppressing the effects of thermal agitation and simultaneously reducing the average grain diameter and the standard deviation of magnetic crystal grains constituting a ferromagnetic metal film, without changing the film thickness of a metal under-layer or the film thickness of a ferromagnetic metal layer forming a recording layer, as well as a production method thereof, and a magnetic recording device. The magnetic recording medium includes a ferromagnetic metal layer of a cobalt based alloy formed on a base material with a metal underlayer having chromium as a major constituent disposed there between, wherein a seed layer having at least tungsten is provided between the base material and the metal under-layer, and the seed layer is an islands type film.
    Type: Grant
    Filed: November 28, 2001
    Date of Patent: March 23, 2004
    Inventors: Migaku Takahashi, Satoru Yoshimura, David Djayaprawira, Hiroki Shoji
  • Publication number: 20020127434
    Abstract: The present invention provides a magnetic recording medium with a high normalized coercive force and superior thermal stability, as well as a method of producing such a magnetic recording medium and a magnetic recording device incorporating such a magnetic recording medium. A magnetic recording medium according to the present invention comprises a non-magnetic base material, and a ferromagnetic metal layer of cobalt based alloy formed on top of this base material with a metal underlayer disposed therebetween, and displays a coercive force Hc of at least 2000 (Oe) and an anisotropic magnetic field Hkgrain of at least 10,000 (Oe). Furthermore, magnetic recording media in which the aforementioned metal underlayer and/or the ferromagnetic metal layer are fabricated in a film fabrication chamber with an ultimate vacuum at the 10−9 Torr level are preferred.
    Type: Application
    Filed: December 27, 2001
    Publication date: September 12, 2002
    Inventors: Migaku Takahashi, David Djayaprawira, Kazuya Komiyama, Satoru Yoshimura