Patents by Inventor Guohan Hu

Guohan Hu 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: 20110171493
    Abstract: A magnetic tunnel junction stack including a pinned magnetic layer, a tunnel barrier layer formed of magnesium oxide (MgO), a free magnetic layer adjacent to the tunnel barrier layer, and a layer of vanadium (V) adjacent to the free magnetic layer.
    Type: Application
    Filed: January 8, 2010
    Publication date: July 14, 2011
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Daniel C. Worledge, Guohan Hu, Jonathan Z. Sun
  • Publication number: 20110051503
    Abstract: Magnetic devices, magnetoresistive structures, and methods and techniques associated with the magnetic devices and magnetoresistive structures are presented. For example, a magnetic device is presented. The magnetic device includes a ferromagnet, an antiferromagnet coupled to the ferromagnet, and a nonmagnetic metal proximate to the ferromagnet. The antiferromagnet provides uniaxial anisotropy to the magnetic device. A resistance of the nonmagnetic metal is dependent upon a direction of a magnetic moment of the ferromagnet.
    Type: Application
    Filed: September 3, 2009
    Publication date: March 3, 2011
    Applicant: International Business Machines Corporation
    Inventors: Guohan Hu, Jonathan Zanghong Sun
  • Publication number: 20100320550
    Abstract: Magnetoresistive structures, devices, memories, and methods for forming the same are presented. For example, a magnetoresistive structure includes a ferromagnetic layer, a ferrimagnetic layer coupled to the ferromagnetic layer, a pinned layer and a nonmagnetic spacer layer. A free side of the magnetoresistive structure comprises the ferromagnetic layer and the ferrimagnetic layer. The nonmagnetic spacer layer is at least partly between the free side and the pinned layer. A saturation magnetization of the ferromagnetic layer opposes a saturation magnetization of the ferrimagnetic layer. The nonmagnetic spacer layer may include a tunnel barrier layer, such as one composed of magnesium oxide (MgO), or a nonmagnetic metal layer.
    Type: Application
    Filed: June 23, 2009
    Publication date: December 23, 2010
    Applicant: International Business Machines Corporation
    Inventors: David William Abraham, Guohan Hu, Jonathan Zanhong Sun, Daniel Christopher Worledge
  • Publication number: 20070081277
    Abstract: Methods and apparatus provide a magnetic head that includes a magnetoresistive read sensor disposed between a first magnetic shield and a second magnetic shield. The second magnetic shield is configured to reduce effects on the read sensor due to unevenness in a topography of the read sensor.
    Type: Application
    Filed: October 6, 2005
    Publication date: April 12, 2007
    Inventors: Liesl Folks, Guohan Hu, Yinshi Liu, Kenneth Mackay, Vladimir Nikitin, James Nix, Neil Smith
  • Patent number: 6947235
    Abstract: A patterned perpendicular magnetic recording medium has magnetic islands that contain stacks of individual magnetic cells to provide multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: September 20, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Manfred Albrecht, Olav Hellwig, Guohan Hu, Bruce David Terris
  • Patent number: 6906879
    Abstract: A magnetic recording system, such as a magnetic recording disk drive, uses a patterned perpendicular magnetic recording medium where each magnetic block or island contains a stack of individual magnetic cells to provide multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island, This permits multiple magnetic levels or states to be recorded in each magnetic island.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: June 14, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Manfred Albrecht, Olav Hellwig, Guohan Hu, Bruce David Terris
  • Publication number: 20050122609
    Abstract: A patterned perpendicular magnetic recording medium has magnetic islands that contain stacks of individual magnetic cells to provide multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.
    Type: Application
    Filed: December 3, 2003
    Publication date: June 9, 2005
    Inventors: Manfred Albrecht, Olav Hellwig, Guohan Hu, Bruce Terris
  • Publication number: 20050122612
    Abstract: A magnetic recording system, such as a magnetic recording disk drive, uses a patterned perpendicular magnetic recording medium where each magnetic block or island contains a stack of individual magnetic cells to provide multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.
    Type: Application
    Filed: December 3, 2003
    Publication date: June 9, 2005
    Inventors: Manfred Albrecht, Olav Hellwig, Guohan Hu, Bruce Terris
  • Patent number: 6882488
    Abstract: A magnetic recording method uses a patterned perpendicular magnetic recording medium where each magnetic block or island contains a stack of individual magnetic cells to providing multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: April 19, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Manfred Albrecht, Olav Hellwig, Guohan Hu, Bruce David Terris
  • Patent number: 6865044
    Abstract: A method for magnetic recording uses a fixed write current with thermal assistance to record on a patterned perpendicular magnetic recording medium. The patterned medium has magnetic blocks or islands, each of which contains a stack of individual magnetic cells to provide multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: March 8, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Manfred Albrecht, Olav Hellwig, Guohan Hu, Bruce David Terris