Patents by Inventor Haiwen Xi

Haiwen Xi 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: 20130015543
    Abstract: A magnetic tunnel junction cell having a free layer, a ferromagnetic pinned layer, and a barrier layer therebetween. The free layer has a central ferromagnetic portion and a stabilizing portion radially proximate the central ferromagnetic portion. The construction can be used for both in-plane magnetic memory cells where the magnetization orientation of the magnetic layer is in the stack film plane and out-of-plane magnetic memory cells where the magnetization orientation of the magnetic layer is out of the stack film plane, e.g., perpendicular to the stack plane.
    Type: Application
    Filed: September 12, 2012
    Publication date: January 17, 2013
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Kaizhong Gao, Haiwen Xi
  • 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
  • Patent number: 8334165
    Abstract: Methods for making a programmable metallization memory cell are disclosed.
    Type: Grant
    Filed: April 16, 2010
    Date of Patent: December 18, 2012
    Assignee: Seagate Technology LLC
    Inventors: Haiwen Xi, Ming Sun, Dexin Wang, Shuiyuan Huang, Michael Tang, Song S. Xue
  • 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
  • Patent number: 8320169
    Abstract: An apparatus and method for compensating for asymmetric write current in a non-volatile unit cell. The unit cell comprises a switching device and an asymmetric resistive sense element (RSE), such as an asymmetric resistive random access memory (RRAM) element or an asymmetric spin-torque transfer random access memory (STRAM) element. The RSE is physically oriented within the unit cell relative to the switching device such that a hard direction for programming the RSE is aligned with an easy direction of programming the unit cell, and an easy direction for programming the RSE is aligned with a hard direction for programming the unit cell.
    Type: Grant
    Filed: December 21, 2011
    Date of Patent: November 27, 2012
    Assignee: Seagate Technology LLC
    Inventors: Wenzhong Zhu, Yong Lu, Xiaobin Wang, Yiran Chen, Alan Xuguang Wang, Xiaohua Lou, Haiwen Xi
  • 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
  • Patent number: 8295072
    Abstract: Non-volatile magnetic random access memory (MRAM) devices that include magnetic flip-flop structures that include a magnetization controlling structure; a first tunnel barrier structure; and a magnetization controllable structure that includes a first polarizing layer; and a first stabilizing layer, wherein the first tunnel barrier structure is between the magnetization controllable structure and the magnetization controlling structure and the first polarizing layer is between the first stabilizing layer and the first tunnel barrier structure, wherein the magnetic flip-flop device has two stable overall magnetic; configurations a second tunnel barrier structure and a reference layer, wherein the second tunnel barrier structure is between the magnetic flip-flop device and the reference layer.
    Type: Grant
    Filed: March 29, 2011
    Date of Patent: October 23, 2012
    Assignee: Seagate Technology LLC
    Inventors: Dimitar V. Dimitrov, Olle Gunnar Heinonen, Yiran Chen, Haiwen Xi, Xiaohua Lou
  • Publication number: 20120261778
    Abstract: Spin torque magnetic memory elements that have a pinned layer, two free layers, and a current-blocking insulating layer proximate to at least one of the free layers. The resistive state (e.g., low resistance or high resistance) of the memory elements is altered by passing electric current through the element in one direction. In other words, to change from a low resistance to a high resistance, the direction of electric current is the same as to change from a high resistance to a low resistance. The elements have a unidirectional write scheme.
    Type: Application
    Filed: June 22, 2012
    Publication date: October 18, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Haiwen Xi, Dexin Wang, Dimitar V. Dimitrov, Paul E. Anderson, Song S. Xue
  • Patent number: 8289748
    Abstract: Method and apparatus for tuning a variable resistance resistive sense element of an electronic device. In some embodiments, a value indicative of a selected number of consecutive pulses is stored in a memory location and a resistive sense element (RSE) is set to a baseline RSE resistance. A tuning operation is performed by applying the selected number of consecutive pulses to the RSE to tune the baseline RSE resistance to a final adjusted resistance.
    Type: Grant
    Filed: July 6, 2009
    Date of Patent: October 16, 2012
    Assignee: Seagate Technology LLC
    Inventors: Brian S. Lee, Haiwen Xi, Patrick J. Ryan, Rod Bowman
  • 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
  • Patent number: 8288023
    Abstract: A magnetic tunnel junction cell having a free layer, a ferromagnetic pinned layer, and a barrier layer therebetween. The free layer has a central ferromagnetic portion and a stabilizing portion radially proximate the central ferromagnetic portion. The construction can be used for both in-plane magnetic memory cells where the magnetization orientation of the magnetic layer is in the stack film plane and out-of-plane magnetic memory cells where the magnetization orientation of the magnetic layer is out of the stack film plane, e.g., perpendicular to the stack plane.
    Type: Grant
    Filed: December 23, 2010
    Date of Patent: October 16, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi
  • 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
  • Patent number: 8287944
    Abstract: A magnetic tunnel junction cell having a free layer, a ferromagnetic pinned layer, and a barrier layer therebetween. The free layer has a central ferromagnetic portion and a stabilizing portion radially proximate the central ferromagnetic portion. The construction can be used for both in-plane magnetic memory cells where the magnetization orientation of the magnetic layer is in the stack film plane and out-of-plane magnetic memory cells where the magnetization orientation of the magnetic layer is out of the stack film plane, e.g., perpendicular to the stack plane.
    Type: Grant
    Filed: March 28, 2011
    Date of Patent: October 16, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi
  • Publication number: 20120257446
    Abstract: A memory unit includes a magnetic tunnel junction data cell electrically coupled to a bit line and a word line. The magnetic tunnel junction data cell is configured to switch between a high resistance state and a low resistance state by passing a unipolar voltage across the magnetic tunnel junction data cell. A diode is electrically coupled between the magnetic tunnel junction data cell and the word line or bit line. A voltage source provides the unipolar voltage across the magnetic tunnel junction data cell that writes the high resistance state and the low resistance state.
    Type: Application
    Filed: June 20, 2012
    Publication date: October 11, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaohua Lou, Haiwen Xi
  • Publication number: 20120250405
    Abstract: Memory units that have a magnetic tunnel junction cell that utilizes spin torque and a current induced magnetic field to assist in the switching of the magnetization orientation of the free layer of the magnetic tunnel junction cell. The memory unit includes a spin torque current source for passing a current through the magnetic tunnel junction cell, the spin torque current source having a direction perpendicular to the magnetization orientations, and also includes a magnetic ampere field current source is oriented in a direction orthogonal or at some angles to the magnetization orientations.
    Type: Application
    Filed: June 8, 2012
    Publication date: October 4, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaobin Wang, Haiwen Xi, Hongyue Liu, Insik Jin, Andreas Roelofs, Eileen Yan, Dimitar V. Dimitrov
  • Publication number: 20120248558
    Abstract: A spin-transfer torque memory unit includes a free magnetic layer having a magnetic easy axis; a reference magnetic element having a magnetization orientation that is pinned in a reference direction; an electrically insulating and non-magnetic tunneling barrier layer separating the free magnetic layer from the magnetic reference element; and a compensation element adjacent to the free magnetic layer. The compensation element applies a bias field on the magnetization orientation of the free magnetic layer. The bias field is formed of a first vector component parallel to the easy axis of the free magnetic layer and a second vector component orthogonal to the easy axis of the free magnetic layer. The bias field reduces a write current magnitude required to switch the direction of the magnetization orientation of the free magnetic layer.
    Type: Application
    Filed: May 22, 2012
    Publication date: October 4, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Wenzhong Zhu, Olle Heinonen
  • Patent number: 8270204
    Abstract: Magnetic shift tracks or magnetic strips, to which application of a rotating magnetic field or by rotation of the strip itself allows accurate determination of domain wall movement. One particular embodiment is a method of determining a position of a domain wall in a magnetic strip. The method includes applying a rotating magnetic field to the magnetic strip, the magnetic field rotating around a longitudinal axis of the magnetic strip, and after applying the magnetic field, determining a displacement of the domain wall to a second position.
    Type: Grant
    Filed: July 9, 2009
    Date of Patent: September 18, 2012
    Assignee: Seagate Technology LLC
    Inventors: Xiaobin Wang, Haiwen Xi, Yiran Chen, Yuan Yan, Jun Zheng
  • 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
  • Patent number: 8243503
    Abstract: The present invention relates to a memory cell including a first reference layer having a first magnetization with a first magnetization direction and a second reference layer having a second magnetization with a second magnetization direction substantially perpendicular to the first magnetization direction. A storage layer is disposed between the first reference layer and second reference layer and has a third magnetization direction about 45° from the first magnetization direction and about 135° from the second magnetization direction when the memory cell is in a first data state, and a fourth magnetization direction opposite the third magnetization direction when the memory cell is in a second data state.
    Type: Grant
    Filed: December 1, 2010
    Date of Patent: August 14, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Yiming Shi, Song S. Xue, Sining Mao
  • Patent number: 8233319
    Abstract: A memory unit includes a magnetic tunnel junction data cell electrically coupled to a bit line and a word line. The magnetic tunnel junction data cell is configured to switch between a high resistance state and a low resistance state by passing a unipolar voltage across the magnetic tunnel junction data cell. A diode is electrically coupled between the magnetic tunnel junction data cell and the word line or bit line. A voltage source provides the unipolar voltage across the magnetic tunnel junction data cell that writes the high resistance state and the low resistance state.
    Type: Grant
    Filed: July 18, 2008
    Date of Patent: July 31, 2012
    Assignee: Seagate Technology LLC
    Inventors: Xiaohua Lou, Haiwen Xi