Patents by Inventor Katsumi Suemitsu

Katsumi Suemitsu 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).

  • Publication number: 20060261425
    Abstract: A magnetic memory includes a substrate, a lower portion structure of a magnetic element, an upper portion structure of the magnetic element, and a sidewall insulating film. The lower portion structure of the magnetic element is a portion of the magnetic element provided on the upside of the substrate. The upper portion structure of the magnetic element is a remaining portion of the magnetic element provided on the upside of the lower portion structure of the magnetic element. The sidewall insulating film is provided to surround the upper portion structure of the magnetic element and is formed of an insulating material. That is, the lower portion structure of the magnetic element is formed from one layer or a plurality of layers on a side close to the substrate, among a plurality of laminated films of the magnetic element provided on the upside of the substrate.
    Type: Application
    Filed: September 19, 2003
    Publication date: November 23, 2006
    Applicant: NEC CORPORATION
    Inventors: Katsumi Suemitsu, Kuniko Kikuta
  • Publication number: 20050064157
    Abstract: A magnetic memory according to the present invention comprises: a single magnetic memory cell having at least first to third magnetic layers, a first tunnel insulating layer between the first and second magnetic layers and a second tunnel insulating layer between the second and third magnetic layers. The resistance between the first and third magnetic layers when magnetization of the first and second magnetic layers are in opposite directions is different from the resistance between the second and third magnetic layers when magnetization of the second and third magnetic layers are in opposite directions. Multiple data are therefore stored into the memory cell.
    Type: Application
    Filed: November 2, 2004
    Publication date: March 24, 2005
    Inventors: Takeshi Okazawa, Katsumi Suemitsu
  • Patent number: 6812537
    Abstract: A magnetic memory according to the present invention comprises: a single magnetic memory cell having at least first to third magnetic layers, a first tunnel insulating layer between the first and second magnetic layers and a second tunnel insulating layer between the second and third magnetic layers. The resistance between the first and third magnetic layers when magnetization of the first and second magnetic layers are in opposite directions is different from the resistance between the second and third magnetic layers when magnetization of the second and third magnetic layers are in opposite directions. Multiple data are therefore stored into the memory cell.
    Type: Grant
    Filed: May 8, 2002
    Date of Patent: November 2, 2004
    Assignee: NEC Electronics Corporation
    Inventors: Takeshi Okazawa, Katsumi Suemitsu
  • Publication number: 20020167033
    Abstract: A magnetic memory according to the present invention comprises: a single magnetic memory cell having at least first to third magnetic layers, a first tunnel insulating layer between the first and second magnetic layers and a second tunnel insulating layer between the second and third magnetic layers. The resistance between the first and third magnetic layers when magnetization of the first and second magnetic layers are in opposite directions is different from the resistance between the second and third magnetic layers when magnetization of the second and third magnetic layers are in opposite directions. Multiple data are therefore stored into the memory cell.
    Type: Application
    Filed: May 8, 2002
    Publication date: November 14, 2002
    Inventors: Takeshi Okazawa, Katsumi Suemitsu
  • Patent number: 6246544
    Abstract: A magnetic disk drive for recording and reproducing data out of a magnetic disk with a magnetoresisive (MR) head contacting the disk is disclosed. When the MR device is spaced from the surface of the medium by a recess of less than 15 nm inclusive, the surface of the medium is provided with a sheet resistance of less than 5 &OHgr;/cm2 inclusive. When the sheet resistance is greater than 5 &OHgr;/cm2, the recess is selected to be 16 nm or above. To enhance a frequency characteristic, the surface of the disk is provided with an undulation period of greater than 2 &mgr;m inclusive in the direction of movement of a head and a surface roughness of less than 1 nm inclusive. With this configuration, the disk drive obviates electrical faults ascribable to the sliding contact of the head and disk.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: June 12, 2001
    Assignee: NEC Corporation
    Inventors: Katsumichi Tagami, Shinzo Tsuboi, Katsumi Suemitsu