Patents by Inventor Yuankai Zheng

Yuankai Zheng 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).

  • MAGNETIC STACK HAVING REFERENCE LAYERS WITH ORTHOGONAL MAGNETIZATION ORIENTATION DIRECTIONS
    Publication number: 20130001720
    Abstract: A magnetic cell includes a ferromagnetic free layer having a free magnetization orientation direction and a first ferromagnetic pinned reference layer having a first reference magnetization orientation direction that is parallel or anti-parallel to the free magnetization orientation direction. A first oxide barrier layer is between the ferromagnetic free layer and the first ferromagnetic pinned reference layer. The magnetic cell further includes a second ferromagnetic pinned reference layer having a second reference magnetization orientation direction that is orthogonal to the first reference magnetization orientation direction. The ferromagnetic free layer is between the first ferromagnetic pinned reference layer and the second ferromagnetic pinned reference layer.
    Type: Application
    Filed: September 13, 2012
    Publication date: January 3, 2013
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Zheng Gao, Wenzhong Zhu, Wonjoon Jung, Haiwen Xi
  • NON VOLATILE MEMORY INCLUDING STABILIZING STRUCTURES
    Publication number: 20120299135
    Abstract: An apparatus that includes a magnetic structure including a reference layer; and a free layer; an exchange coupling spacer layer; and a stabilizing layer, wherein the exchange coupling spacer layer is between the magnetic structure and the stabilizing layer and exchange couples the free layer of the magnetic structure to the stabilizing layer.
    Type: Application
    Filed: August 7, 2012
    Publication date: November 29, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Xiaobin Wang, Wei Tian, Xiaohua Lou
  • Magnetic stack having reference layers with orthogonal magnetization orientation directions
    Patent number: 8294227
    Abstract: A magnetic cell includes a ferromagnetic free layer having a free magnetization orientation direction and a first ferromagnetic pinned reference layer having a first reference magnetization orientation direction that is parallel or anti-parallel to the free magnetization orientation direction. A first oxide barrier layer is between the ferromagnetic free layer and the first ferromagnetic pinned reference layer. The magnetic cell further includes a second ferromagnetic pinned reference layer having a second reference magnetization orientation direction that is orthogonal to the first reference magnetization orientation direction. The ferromagnetic free layer is between the first ferromagnetic pinned reference layer and the second ferromagnetic pinned reference layer.
    Type: Grant
    Filed: July 5, 2011
    Date of Patent: October 23, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Zheng Gao, Wenzhong Zhu, Wonjoon Jung, Haiwen Xi
  • Magnetic tunnel junction with electronically reflective insulative spacer
    Patent number: 8289758
    Abstract: Magnetic tunnel junctions having a specular insulative spacer are disclosed. The magnetic tunnel junction includes a free magnetic layer, a reference magnetic layer, an electrically insulating and non-magnetic tunneling barrier layer separating the free magnetic layer from the reference magnetic layer, and an electrically insulating and electronically reflective layer positioned to reflect at least a portion of electrons back into the free magnetic layer.
    Type: Grant
    Filed: November 11, 2010
    Date of Patent: October 16, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Wei Tian, Dexin Wang, Zheng Gao, Xiaobin Wang
  • Non-volatile memory cell with precessional switching
    Patent number: 8289759
    Abstract: A method and apparatus for writing data to a non-volatile memory cell, such as a spin-torque transfer random access memory (STRAM) memory cell. In some embodiments, a selected resistive state is written to a magnetic tunneling structure by applying a succession of indeterminate write pulses thereto until the selected resistive state is verified.
    Type: Grant
    Filed: April 21, 2011
    Date of Patent: October 16, 2012
    Assignee: Seagate Technology LLC
    Inventors: Xiaobin Wang, Yong Lu, Haiwen Xi, Yuankai Zheng, Yiran Chen, Harry Hongyue Liu, Dimitar V. Dimitrov, Wei Tian, Brian S. Lee
  • Non volatile memory including stabilizing structures
    Patent number: 8289756
    Abstract: An apparatus that includes a magnetic structure including a reference layer; and a free layer; an exchange coupling spacer layer; and a stabilizing layer, wherein the exchange coupling spacer layer is between the magnetic structure and the stabilizing layer and exchange couples the free layer of the magnetic structure to the stabilizing layer.
    Type: Grant
    Filed: July 13, 2009
    Date of Patent: October 16, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Xiaobin Wang, Wei Tian, Xiaohua Lou
  • MAGNETIC TUNNEL JUNCTION WITH COMPENSATION ELEMENT
    Publication number: 20120257447
    Abstract: A magnetic tunnel junction having a compsensation element is disclosed. The magnetic tunnel junction includes a reference element, and a compensation element having an opposite magnetization moment to a magnetization moment of the reference element. A free magnetic layer is between the reference element and the compensation element, and an electrically insulating and non-magnetic tunneling barrier layer separates the free magnetic layer from the reference element. The free magnetic layer includes Co100-X-YFeXBY wherein X is a value being greater than 30 and Y is a value being greater than 15.
    Type: Application
    Filed: June 20, 2012
    Publication date: October 11, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Wei Tian, Xiaobin Wang, Xiaohua Lou
  • MAGNETIC STACK WITH OXIDE TO REDUCE SWITCHING CURRENT
    Publication number: 20120241886
    Abstract: A magnetic stack having a ferromagnetic free layer, a metal oxide layer that is antiferromagnetic at a first temperature and non-magnetic at a second temperature higher than the first temperature, a ferromagnetic pinned reference layer, and a non-magnetic spacer layer between the free layer and the reference layer. During a writing process, the metal oxide layer is non-magnetic. For magnetic memory cells, such as magnetic tunnel junction cells, the metal oxide layer provides reduced switching currents.
    Type: Application
    Filed: June 8, 2012
    Publication date: September 27, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaohua Lou, Yuankai Zheng, Wenzhong Zhu, Wei Tian, Zheng Gao
  • THERMALLY ASSISTED MULTI-BIT MRAM
    Publication number: 20120230092
    Abstract: Methods of writing to a multi-bit MRAM memory unit are described. The method includes to self-detected writing to a multi-bit (i.e., multilevel) thermally assisted MRAM. The self-detected writing increases a reading margin between data state levels and decreases reading margin variability due to cell resistance variation.
    Type: Application
    Filed: May 18, 2012
    Publication date: September 13, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Haiwen Xi
  • Magnetic stack with oxide to reduce switching current
    Patent number: 8217478
    Abstract: A magnetic stack having a ferromagnetic free layer, a metal oxide layer that is antiferromagnetic at a first temperature and non-magnetic at a second temperature higher than the first temperature, a ferromagnetic pinned reference layer, and a non-magnetic spacer layer between the free layer and the reference layer. During a writing process, the metal oxide layer is non-magnetic. For magnetic memory cells, such as magnetic tunnel junction cells, the metal oxide layer provides reduced switching currents.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: July 10, 2012
    Assignee: Seagate Technology LLC
    Inventors: Xiaohua Lou, Yuankai Zheng, Wenzhong Zhu, Wei Tian, Zheng Gao
  • Magnetic tunnel junction with compensation element
    Patent number: 8213222
    Abstract: A magnetic tunnel junction having a compsensation element is disclosed. The magnetic tunnel junction includes a reference element, and a compensation element having an opposite magnetization moment to a magnetization moment of the reference element. A free magnetic layer is between the reference element and the compensation element, and an electrically insulating and non-magnetic tunneling barrier layer separates the free magnetic layer from the reference element. The free magnetic layer includes Co100-X-YFeXBY wherein X is a value being greater than 30 and Y is a value being greater than 15.
    Type: Grant
    Filed: August 16, 2011
    Date of Patent: July 3, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Wei Tian, Xiaobin Wang, Xiaohua Lou
  • Thermally assisted multi-bit MRAM
    Patent number: 8199564
    Abstract: Methods of writing to a multi-bit MRAM memory unit are described. The method includes to self-detected writing to a multi-bit (i.e., multilevel) thermally assisted MRAM. The self-detected writing increases a reading margin between data state levels and decreases reading margin variability due to cell resistance variation.
    Type: Grant
    Filed: June 15, 2011
    Date of Patent: June 12, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Haiwen Xi
  • Spin-transfer torque memory self-reference read method
    Patent number: 8194444
    Abstract: Self-reference reading a magnetic tunnel junction data cell methods are disclosed. An illustrative method includes applying a read voltage across a magnetic tunnel junction data cell and forming a read current. The magnetic tunnel junction data cell has a first resistance state. The read voltage is sufficient to switch the magnetic tunnel junction data cell resistance. The method includes detecting the read current and determining if the read current remains constant during the applying step. If the read current remains constant during the applying step, then the first resistance state of the magnetic tunnel junction data cell is the resistance state that the read voltage was sufficient to switch the magnetic tunnel junction data cell to.
    Type: Grant
    Filed: December 15, 2010
    Date of Patent: June 5, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Yiran Chen, Xiaobin Wang, Zheng Gao, Dimitar V. Dimitrov, Wenzhong Zhu, Yong Lu
  • Static magnetic field assisted resistive sense element
    Patent number: 8183654
    Abstract: Apparatus and associated method for writing data to a non-volatile memory cell, such as spin-torque transfer random access memory (STRAM). In accordance with some embodiments, a resistive sense element (RSE) has a heat assist region, magnetic tunneling junction (MTJ), and pinned region. When a first logical state is written to the MTJ with a spin polarized current, the pinned and heat assist regions each have a substantially zero net magnetic moment. When a second logical state is written to the MTJ with a static magnetic field, the pinned region has a substantially zero net magnetic moment and the heat assist region has a non-zero net magnetic moment.
    Type: Grant
    Filed: May 27, 2011
    Date of Patent: May 22, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Xiaohua Lou, Haiwen Xi, Michael Xuefei Tang
  • Memory Cell With Phonon-Blocking Insulating Layer
    Publication number: 20120119313
    Abstract: An apparatus and associated method for a non-volatile memory cell with a phonon-blocking insulating layer. In accordance with various embodiments, a magnetic stack has a tunnel junction, ferromagnetic free layer, pinned layer, and an insulating layer that is constructed of an electrically and thermally insulative material that blocks phonons while allowing electrical transmission through at least one conductive feature.
    Type: Application
    Filed: November 16, 2010
    Publication date: May 17, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Xiaohua Lou, Wei Tian, Zheng Gao, Haiwen Xi
  • MAGNETIC TUNNEL JUNCTION CELLS HAVING PERPENDICULAR ANISOTROPY AND ENHANCEMENT LAYER
    Publication number: 20120104522
    Abstract: A magnetic tunnel junction cell that includes a ferromagnetic free layer; an enhancement layer having a thickness of at least about 15 ?; an oxide barrier layer; and a ferromagnetic reference layer, wherein the enhancement layer and the oxide barrier layer are positioned between the ferromagnetic reference layer and ferromagnetic free layer and the oxide barrier layer is positioned adjacent the ferromagnetic reference layer, and wherein the ferromagnetic free layer, the ferromagnetic reference layer, and the enhancement layer all have magnetization orientations that are out-of-plane
    Type: Application
    Filed: November 1, 2010
    Publication date: May 3, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Wonjoon Jung, Yuankai Zheng, Zheng Gao
  • Magnetic Memory Element With Multi-Domain Storage Layer
    Publication number: 20120106239
    Abstract: An apparatus and method for enhancing data writing and retention to a magnetic memory element, such as in a non-volatile data storage array. In accordance with various embodiments, a programmable memory element has a reference layer and a storage layer. The reference layer is provided with a fixed magnetic orientation. The storage layer is programmed to have a first region with a magnetic orientation antiparallel to said fixed magnetic orientation, and a second region with a magnetic orientation parallel to said fixed magnetic orientation. A thermal assist layer may be incorporated into the memory element to enhance localized heating of the storage layer to aid in the transition of the first region from parallel to antiparallel magnetic orientation during a write operation.
    Type: Application
    Filed: November 3, 2010
    Publication date: May 3, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Haiwen Xi, Yuankai Zheng, Xiaobin Wang, Dimitar V. Dimitrov, Pat J. Ryan
  • STRAM WITH COMPOSITE FREE MAGNETIC ELEMENT
    Publication number: 20120039115
    Abstract: Spin-transfer torque memory includes a composite free magnetic element, a reference magnetic element having a magnetization orientation that is pinned in a reference direction, and an electrically insulating and non-magnetic tunneling barrier layer separating the composite free magnetic element from the magnetic reference element. The free magnetic element includes a hard magnetic layer exchanged coupled to a soft magnetic layer. The composite free magnetic element has a magnetization orientation that can change direction due to spin-torque transfer when a write current passes through the spin-transfer torque memory unit.
    Type: Application
    Filed: October 21, 2011
    Publication date: February 16, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Kaizhong Gao, Olle Heinonen, Wenzhong Zhu
  • MAGNETIC STACK WITH OXIDE TO REDUCE SWITCHING CURRENT
    Publication number: 20120021535
    Abstract: A magnetic stack having a ferromagnetic free layer, a metal oxide layer that is antiferromagnetic at a first temperature and non-magnetic at a second temperature higher than the first temperature, a ferromagnetic pinned reference layer, and a non-magnetic spacer layer between the free layer and the reference layer. During a writing process, the metal oxide layer is non-magnetic. For magnetic memory cells, such as magnetic tunnel junction cells, the metal oxide layer provides reduced switching currents.
    Type: Application
    Filed: September 29, 2011
    Publication date: January 26, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaohua Lou, Yuankai Zheng, Wenzhong Zhu, Wei Tian, Zheng Gao
  • MAGNETIC STACK WITH LAMINATED LAYER
    Publication number: 20120018788
    Abstract: A magnetic stack with a multilayer free layer having a switchable magnetization orientation, the free layer comprising a first ferromagnetic portion and a second ferromagnetic portion with an electrically conducting non-magnetic intermediate layer between the first portion and the second portion. The magnetic stack also includes a first ferromagnetic reference layer having a pinned magnetization orientation, a first non-magnetic spacer layer between the free layer and the first reference layer, a second ferromagnetic reference layer having a pinned magnetization orientation, and a second non-magnetic spacer layer between the free layer and the second reference layer.
    Type: Application
    Filed: September 29, 2011
    Publication date: January 26, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Xuebing Feng, Zheng Gao