Patents by Inventor Grace S. Lim

Grace S. Lim 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: 4749628
    Abstract: A vertical magnetic recording medium is formed of multiple layers, each layer comprising a cobalt-platinum (CoPt) magnetic film formed on a hexagonal-close-packed (HCP) necleating film. The thickness of each CoPt film in each layer is sufficiently thin to assure that the film has perpendicular magnetic anisotropy. The magnetic properties of the multilayered magnetic film structure can be varied by varying the thickness of the individual films and the number of layers.
    Type: Grant
    Filed: April 29, 1986
    Date of Patent: June 7, 1988
    Assignee: International Business Machines Corporation
    Inventors: Richard H. Ahlert, James K. Howard, Grace S. Lim
  • Patent number: 4654276
    Abstract: An improved cobalt-platinum (CoPt) thin film metal alloy media for horizontal magnetic recording has a coercivity substantially greater than prior CoPt thin film metal alloy media. A tungsten underlayer between the substrate and the CoPt magnetic layer improves the coercivity above that of media wiht conventional underlayers, such as chromium. The coercivity of the CoPt layer can be increased even further if the CoPt film is deposited in such a manner as to form an intermetallic compound of Co.sub.3 W in the interface region between the tungsten underlayer and the CoPt magnetic layer. The tungsten underlayer also improves the magnetic properties of the media when the magnetic layer is an alloy of cobalt-platinum-chromium (CoPtCr).
    Type: Grant
    Filed: April 29, 1986
    Date of Patent: March 31, 1987
    Assignee: International Business Machines Corporation
    Inventors: Richard H. Ahlert, James K. Howard, Grace S. Lim