Patents by Inventor Zhitao Diao

Zhitao Diao 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: 20070159734
    Abstract: A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, nonmagnetic spacer, and free layers. The spacer layer resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The magnetic element may also include a barrier layer, a second pinned layer. Alternatively, second pinned and second spacer layers and a second free layer magnetostatically coupled to the free layer are included. In one aspect, the free layer(s) include ferromagnetic material(s) diluted with nonmagnetic material(s) and/or ferrimagnetically doped to provide low saturation magnetization(s).
    Type: Application
    Filed: March 13, 2007
    Publication date: July 12, 2007
    Inventors: Paul Nguyen, Yiming Huai, Zhitao Diao, Frank Albert
  • Patent number: 7242045
    Abstract: A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, nonmagnetic spacer, and free layers. The spacer layer resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The magnetic element may also include a barrier layer, a second pinned layer. Alternatively, second pinned and second spacer layers and a second free layer magnetostatically coupled to the free layer are included. In one aspect, the free layer(s) include ferromagnetic material(s) diluted with nonmagnetic material(s) and/or ferrimagnetically doped to provide low saturation magnetization(s).
    Type: Grant
    Filed: February 19, 2004
    Date of Patent: July 10, 2007
    Assignee: Grandis, Inc.
    Inventors: Paul P. Nguyen, Yiming Huai, Zhitao Diao, Frank Albert
  • Publication number: 20070120211
    Abstract: A method and system for providing a magnetic element are described. The method and system include providing a single pinned layer, a free layer, and a spacer layer between the pinned and free layers. The spacer layer is nonmagnetic. The magnetic element is configured to allow the free layer to be switched due to spin transfer when a write current is passed through the magnetic element. The free layer is a simple free layer. In one aspect, the method and system include providing a spin engineered layer adjacent to the free layer. The spin engineered layer is configured to more strongly scatter majority electrons than minority electrons. In another aspect, at least one of the pinned, free, and spacer layers is a spin engineered layer having an internal spin engineered layer configured to more strongly scatter majority electrons than minority electrons. In this aspect, the magnetic element may include another pinned layer and a barrier layer between the free and pinned layers.
    Type: Application
    Filed: January 29, 2007
    Publication date: May 31, 2007
    Inventors: Zhitao Diao, Yiming Huai, Thierry Valet, Paul Nguyen, Mahendra Pakala
  • Publication number: 20070085068
    Abstract: A method and system for providing a magnetic element and a memory incorporating the magnetic element is described. The method and system for providing the magnetic element include providing a pinned layer, a spacer layer, and a free layer. The free layer includes granular free layer having a plurality of grains in a matrix, the spacer layer residing between the pinned layer and the free layer. The magnetic element is configured to allow the granular free layer to be switched due to spin-transfer when a write current is passed through the magnetic element.
    Type: Application
    Filed: October 14, 2005
    Publication date: April 19, 2007
    Inventors: Dmytro Apalkov, Zhitao Diao, Yunfei Ding, Yiming Huai
  • Publication number: 20070063236
    Abstract: Magnetic multilayer structures, such as magnetic or magnetoresistive tunnel junctions (MTJs) and spin valves, having a magnetic biasing layer formed next to and magnetically coupled to the free ferromagnetic layer to achieve a desired stability against fluctuations caused by, e.g., thermal fluctuations and astray fields. Stable MTJ cells with low aspect ratios can be fabricated using CMOS processing for, e.g., high-density MRAM memory devices and other devices, using the magnetic biasing layer. Such multilayer structures can be programmed using spin transfer induced switching by driving a write current perpendicular to the layers.
    Type: Application
    Filed: September 20, 2005
    Publication date: March 22, 2007
    Inventors: Yiming Huai, Zhitao Diao, Eugene Chen
  • Publication number: 20070063237
    Abstract: Magnetic multilayer structures, such as magnetic or magnetoresistive tunnel junctions (MTJs) and spin valves, having a magnetic biasing layer formed next to and magnetically coupled to the free ferromagnetic layer to achieve a desired stability against fluctuations caused by, e.g., thermal fluctuations and astray fields. Stable MTJ cells with low aspect ratios can be fabricated using CMOS processing for, e.g., high-density MRAM memory devices and other devices, using the magnetic biasing layer. Such multilayer structures can be programmed using spin transfer induced switching by driving a write current perpendicular to the layers. Each free ferromagnetic layer can include two or more layers and may be a multilayered free ferromagnetic stack that includes first and second ferromagnetic layers and a non-magnetic spacer between the first and second ferromagnetic layers.
    Type: Application
    Filed: August 1, 2006
    Publication date: March 22, 2007
    Inventors: Yiming Huai, Zhitao Diao, Eugene Chen
  • Patent number: 7187577
    Abstract: A method and system for providing a magnetic memory is included. The method and system include providing at least one magnetic storage cell and at least one dummy resistor coupled with the at least one magnetic storage cell at least for a write operation of the at least one magnetic storage cell. Each of the at least one magnetic storage cell includes a magnetic element and a selection device coupled with the magnetic element. The magnetic element being programmed by a first write current driven through the magnetic element in a first direction and a second write current driven through the magnetic element in a second direction. The selection device is configured to be coupled between the magnetic element and the at least one dummy resistor.
    Type: Grant
    Filed: November 23, 2005
    Date of Patent: March 6, 2007
    Assignee: Grandis, Inc.
    Inventors: Lien-Chang Wang, Zhitao Diao, Yunfei Ding
  • Publication number: 20060279981
    Abstract: A method and system for providing a magnetic memory is described. The method and system include providing a plurality of magnetic storage cells, a plurality of word lines, and a plurality of bit lines. Each of the plurality of magnetic storage cells includes a plurality of magnetic elements and at least one selection transistor. Each of the plurality of magnetic elements is capable of being programmed using spin transfer induced switching by a write current driven through the magnetic element. Each of the plurality of magnetic elements has a first end and a second end. The at least one selection transistor is coupled to the first end of each of the plurality of magnetic elements. The plurality of word lines is coupled with the plurality of selection transistors and selectively enables a portion of the plurality of selection transistors.
    Type: Application
    Filed: June 8, 2005
    Publication date: December 14, 2006
    Inventors: Zhitao Diao, Yiming Huai, Mahendra Pakala, Zhenghong Qian
  • Publication number: 20060128038
    Abstract: A method and system for providing a magnetic element are disclosed. The method and system include providing a pinned layer, a free layer, and a spacer layer between the pinned layer and the free layer. The spacer layer is insulating and has an ordered crystal structure. The spacer layer is also configured to allow tunneling through the spacer layer. In one aspect, the free layer is comprised of a single magnetic layer having a particular crystal structure and texture with respect to the spacer layer. In another aspect, the free layer is comprised of two sublayers, the first sublayer having a particular crystal structure and texture with respect to the spacer layer and the second sublayer having a lower moment. In still another aspect, the method and system also include providing a second pinned layer and a second spacer layer that is nonmagnetic and resides between the free layer and the second pinned layer.
    Type: Application
    Filed: December 5, 2005
    Publication date: June 15, 2006
    Inventors: Mahendra Pakala, Thierry Valet, Yiming Huai, Zhitao Diao
  • Publication number: 20060049472
    Abstract: A method and system for providing a magnetic element is disclosed. The method and system include providing a pinned layer, a free layer, and a spacer layer between the pinned and free layers. The spacer layer is nonmagnetic. The magnetic element is configured to allow the free layer to be switched due to spin transfer when a write current is passed through the magnetic element. In one aspect, the method and system include providing a spin engineered layer adjacent to the free layer. The spin engineered layer is configured to more strongly scatter majority electrons than minority electrons. In another aspect, at least one of the pinned, free, and spacer layers is a spin engineered layer having an internal spin engineered layer configured to more strongly scatter majority electrons than minority electrons. In this aspect, the magnetic element may include another pinned layer and a barrier layer between the free and pinned layers.
    Type: Application
    Filed: September 9, 2004
    Publication date: March 9, 2006
    Inventors: Zhitao Diao, Yiming Huai, Thierry Valet, Paul Nguyen, Mahendra Pakala
  • Publication number: 20050184839
    Abstract: A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, nonmagnetic spacer, and free layers. The spacer layer resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The magnetic element may also include a barrier layer, a second pinned layer. Alternatively, second pinned and second spacer layers and a second free layer magnetostatically coupled to the free layer are included. In one aspect, the free layer(s) include ferromagnetic material(s) diluted with nonmagnetic material(s) and/or ferrimagnetically doped to provide low saturation magnetization(s).
    Type: Application
    Filed: February 19, 2004
    Publication date: August 25, 2005
    Inventors: Paul Nguyen, Yiming Huai, Zhitao Diao, Frank Albert
  • Patent number: 6888704
    Abstract: A method and system for providing a magnetoresistive sensor and a read head that includes the magnetoresistive sensor is disclosed. The method and system include providing a pinned layer, a nonmagnetic spacer layer and a composite sensor layer. The pinned layer has a first magnetization that is pinned in a particular direction. The nonmagnetic spacer layer resides between the composite sensor layer and the pinned layer. The composite sensor layer includes a CoFe layer and a composite layer adjacent to the CoFe layer. The composite layer includes CoFe and at least one of Ta, Hf, Ti, Nb, Zr, Au, Ag, Cu, B, C, O2, H2 and N2.
    Type: Grant
    Filed: January 22, 2003
    Date of Patent: May 3, 2005
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Zhitao Diao, Min Zhou, Lifan Chen, Wei Xiong