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 sensor having a high spin polarization reference layer
    Patent number: 8582253
    Abstract: A magnetic sensor configured to reside in proximity to a recording medium during use having a high spin polarization reference layer stack above AFM layers. The reference layer stack comprises a first boron-free ferromagnetic layer above the AFM coupling layer; a magnetic coupling layer on and in contact with the first boron-free ferromagnetic layer; a second ferromagnetic layer comprising boron deposited on and contact with the magnetic coupling layer; and a boron-free third ferromagnetic layer on and in contact the second ferromagnetic layer. A barrier layer is deposited on and in contact with the boron-free third ferromagnetic layer. In one aspect of the invention, the magnetic coupling layer may comprise at least one of Ta, Ti, or Hf. A process for providing the magnetic sensor is also provided.
    Type: Grant
    Filed: June 4, 2012
    Date of Patent: November 12, 2013
    Assignee: Western Digital (Fremont), LLC
    Inventors: Yuankai Zheng, Qunwen Leng, Mahendra Pakala, Zhitao Diao, Christian Kaiser, Cheng-Han Yang
  • Magnetic Memory Element with Multi-Domain Storage Layer
    Publication number: 20130292784
    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: July 3, 2013
    Publication date: November 7, 2013
    Inventors: Haiwen Xi, Yuankai Zheng, Xiaobin Wang, Dimitar V. Dimitrov, Pat J. Ryan
  • MAGNETIC STACK HAVING ASSIST LAYERS
    Publication number: 20130228884
    Abstract: A magnetic tunnel junction having a ferromagnetic free layer and a ferromagnetic pinned reference layer, each having an out-of-plane magnetic anisotropy and an out-of-plane magnetization orientation, the ferromagnetic free layer switchable by spin torque. The magnetic tunnel junction includes a ferromagnetic assist layer proximate the free layer, the assist layer having a low magnetic anisotropy less than 700 Oe and positioned to apply a magnetic field on the free layer.
    Type: Application
    Filed: April 5, 2013
    Publication date: September 5, 2013
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Zheng Gao, Wonjoon Jung, Xuebing Feng, Xiaohue Lou, Haiwen Xi
  • STRAM WITH COMPOSITE FREE MAGNETIC ELEMENT
    Publication number: 20130229862
    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: April 15, 2013
    Publication date: September 5, 2013
    Applicant: SEGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Kaizhong Gao, Olle Heinonen, Wenzhong Zhu
  • Magnetic stack having reference layers with orthogonal magnetization orientation directions
    Patent number: 8519498
    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: September 13, 2012
    Date of Patent: August 27, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Zheng Gao, Wenzhong Zhu, Wonjoon Jung, Haiwen Xi
  • Magnetic tunnel junction with compensation element
    Patent number: 8508988
    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: June 20, 2012
    Date of Patent: August 13, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Wei Tian, Xiaobin Wang, Xiaohua Lou
  • Perpendicular magnetic recording transducer with AFM insertion layer
    Patent number: 8493693
    Abstract: A magnetic sensor is configured to reside in proximity to a recording medium during use. The sensor includes a magnetic top shield and a magnetic bottom shield. A top sensor stack is under the magnetic top shield and includes magnetic sensing layers. A bottom sensor stack is between the magnetic bottom shield and the top sensor stack. The bottom sensor stack includes a magnetic seed stack above the bottom shield, an insertion stack above the magnetic seed stack, and an antiferromagnetic (AFM) layer on and in contact with the insertion stack. A pinned layer is above the AFM layer. An AFM coupling layer is above the pinned layer. In some aspects the insertion stack may include at least one of Ti, Hf, Zr, and Ta. In some aspect, the insertion stack includes a layer of elemental Ti. In other aspects, the insertion stack includes multilayer structures.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: July 23, 2013
    Assignee: Western Digital (Fremont), LLC
    Inventors: Yuankai Zheng, Qunwen Leng, Mahendra Pakala, Cheng-Han Yang
  • Magnetic memory element with multi-domain storage layer
    Patent number: 8482967
    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: Grant
    Filed: November 3, 2010
    Date of Patent: July 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Haiwen Xi, Yuankai Zheng, Xiaobin Wang, Dimitar V. Dimitrov, Pat J. Ryan
  • Static magnetic field assisted resistive sense element
    Patent number: 8466525
    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: March 3, 2011
    Date of Patent: June 18, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Xiaohua Lou, Haiwen Xi, Michael Xuefei Tang
  • Static magnetic field assisted resistive sense element
    Patent number: 8466524
    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: March 3, 2011
    Date of Patent: June 18, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Xiaohua Lou, Haiwen Xi, Michael Xuefei Tang
  • Thermally assisted multi-bit MRAM
    Patent number: 8462543
    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: May 18, 2012
    Date of Patent: June 11, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Haiwen Xi
  • Magnetic stack with oxide to reduce switching current
    Patent number: 8426222
    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: September 29, 2011
    Date of Patent: April 23, 2013
    Assignee: Seagate Technology LLC
    Inventors: Xiaohua Lou, Yuankai Zheng, Wenzhong Zhu, Wei Tian, Zheng Gao
  • Method and system for providing a magnetic read transducer having a bilayer magnetic seed layer
    Patent number: 8422176
    Abstract: A method and system for providing a magnetic read transducer is described. The magnetic read transducer includes a bilayer magnetic seed layer, an antiferromagnetic (AFM) layer, and a read sensor. The bilayer magnetic seed layer includes a Ni1-xFex layer and a Ni1-yFey layer on the Ni1-xFex layer, where x is at least 0.3 and not more than 1 and where y is not more than 0.19. The AFM layer resides on the bilayer magnetic seed layer. The read sensor is on the AFM layer.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: April 16, 2013
    Assignee: Western Digital (Fremont), LLC
    Inventors: Qunwen Leng, Laurence L. Chen, Yimin Guo, Yuankai Zheng, Mahendra Pakala
  • STRAM with composite free magnetic element
    Patent number: 8422279
    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: Grant
    Filed: October 21, 2011
    Date of Patent: April 16, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Kaizhong Gao, Olle Heinonen, Wenzhong Zhu
  • Magnetic memory with phonon glass electron crystal material
    Patent number: 8416619
    Abstract: A magnetic memory unit includes a tunneling barrier separating a free magnetic element and a reference magnetic element. A first phonon glass electron crystal layer is disposed on a side opposing the tunneling barrier of either the free magnetic element or the reference magnetic element. A second phonon glass electron crystal layer also be disposed on a side opposing the tunneling barrier of either the free magnetic element or the reference magnetic element to provide a Peltier effect on the free magnetic element and the reference magnetic element.
    Type: Grant
    Filed: April 19, 2011
    Date of Patent: April 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Haiwen Xi, Dimitar V. Dimitrov, Dexin Wang
  • Magnetic stack having assist layer
    Patent number: 8416620
    Abstract: A magnetic tunnel junction having a ferromagnetic free layer and a ferromagnetic pinned reference layer, each having an out-of-plane magnetic anisotropy and an out-of-plane magnetization orientation, the ferromagnetic free layer switchable by spin torque. The magnetic tunnel junction includes a ferromagnetic assist layer proximate the free layer, the assist layer having a low magnetic anisotropy less than 700 Oe and positioned to apply a magnetic field on the free layer.
    Type: Grant
    Filed: November 11, 2010
    Date of Patent: April 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Zheng Gao, Wonjoon Jung, Xuebing Feng, Xiaohua Lou, Haiwen Xi
  • Memory cell with phonon-blocking insulating layer
    Patent number: 8405171
    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: Grant
    Filed: November 16, 2010
    Date of Patent: March 26, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Xiaohua Lou, Wei Tian, Zheng Gao, Haiwen Xi
  • Flux-closed STRAM with electronically reflective insulative spacer
    Patent number: 8362534
    Abstract: Flux-closed spin-transfer torque memory having a specular insulative spacer is disclosed. A flux-closed spin-transfer torque memory unit includes a multilayer free magnetic element including a first free magnetic layer anti-ferromagnetically coupled to a second free magnetic layer through an electrically insulating and electronically reflective layer. An electrically insulating and non-magnetic tunneling barrier layer separates the free magnetic element from a reference magnetic layer.
    Type: Grant
    Filed: May 25, 2011
    Date of Patent: January 29, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov
  • MAGNETIC TUNNEL JUNCTION WITH ELECTRONICALLY REFLECTIVE INSULATIVE SPACER
    Publication number: 20130001718
    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: Application
    Filed: September 12, 2012
    Publication date: January 3, 2013
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Wei Tian, Dexin Wang, Zheng Gao, Xiaobin Wang
  • 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