Patents by Inventor Luqiao Liu

Luqiao Liu 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: 20180240508
    Abstract: A magneto-resistance random access memory (MRAM) cell includes a transistor, a wire and a magnetic tunnel junction (MTJ). The MTJ includes a fixed layer of fixed magnetic polarity electrically connected with the transistor, a free layer of variable magnetic polarity electrically connected with the wire and an insulator between the fixed and free layers. First current passed through the wire destabilizes the variable magnetic polarity of the free layer. Second current passed through the transistor in one of two directions during first current passage through the wire directs the variable magnetic polarity of the free layer toward a parallel or anti-parallel condition with respect to the fixed magnetic polarity of the fixed layer. A ceasing of the first current prior to a ceasing of the second current sets the variable magnetic polarity of the free layer in the parallel or anti-parallel condition.
    Type: Application
    Filed: March 15, 2018
    Publication date: August 23, 2018
    Inventors: LUQIAO LIU, JONATHAN Z. SUN, DANIEL C. WORLEDGE
  • Patent number: 9947382
    Abstract: Three-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including nonvolatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer.
    Type: Grant
    Filed: November 21, 2016
    Date of Patent: April 17, 2018
    Assignee: Cornell University
    Inventors: Robert A Buhrman, Daniel C Ralph, Chi-Feng Pai, Luqiao Liu
  • Patent number: 9947383
    Abstract: A magneto-resistance random access memory (MRAM) cell includes a transistor, a wire and a magnetic tunnel junction (MTJ). The MTJ includes a fixed layer of fixed magnetic polarity electrically connected with the transistor, a free layer of variable magnetic polarity electrically connected with the wire and an insulator between the fixed and free layers. First current passed through the wire destabilizes the variable magnetic polarity of the free layer. Second current passed through the transistor in one of two directions during first current passage through the wire directs the variable magnetic polarity of the free layer toward a parallel or anti-parallel condition with respect to the fixed magnetic polarity of the fixed layer. A ceasing of the first current prior to a ceasing of the second current sets the variable magnetic polarity of the free layer in the parallel or anti-parallel condition.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: April 17, 2018
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Luqiao Liu, Jonathan Z. Sun, Daniel C. Worledge
  • Patent number: 9799823
    Abstract: Techniques relate to forming a magnetic tunnel junction (MTJ). A magnetic reference layer is formed adjacent to a tunnel barrier layer. The magnetic reference layer includes a pinned layer, a spacer layer adjacent to the pinned layer, and a polarizing enhancement layer adjacent to the spacer layer. A magnetic free layer is formed adjacent to the tunnel barrier layer so as to be opposite the magnetic reference layer.
    Type: Grant
    Filed: April 8, 2016
    Date of Patent: October 24, 2017
    Assignees: INTERNATIONAL BUSINESS MACHINES CORPORATION, SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Guohan Hu, Kwangseok Kim, Younghyun Kim, Junghyuk Lee, Luqiao Liu, Jeong-Heon Park
  • Publication number: 20170294570
    Abstract: Techniques relate to forming a magnetic tunnel junction (MTJ). A magnetic reference layer is formed adjacent to a tunnel barrier layer. The magnetic reference layer includes a pinned layer, a spacer layer adjacent to the pinned layer, and a polarizing enhancement layer adjacent to the spacer layer. A magnetic free layer is formed adjacent to the tunnel barrier layer so as to be opposite the magnetic reference layer.
    Type: Application
    Filed: April 8, 2016
    Publication date: October 12, 2017
    Inventors: GUOHAN HU, KWANGSEOK KIM, YOUNGHYUN KIM, JUNGHYUK LEE, LUQIAO LIU, JEONG-HEON PARK
  • Patent number: 9715917
    Abstract: Magnetic memory devices having an antiferromagnetic reference layer based on Co and Ir are provided. In one aspect, a magnetic memory device includes a reference magnetic layer having multiple Co-containing layers oriented in a stack, wherein adjacent Co-containing layers in the stack are separated by an Ir-containing layer such that the adjacent Co-containing layers in the stack are anti-parallel coupled by the Ir-containing layer therebetween; and a free magnetic layer separated from the reference magnetic layer by a barrier layer. A method of writing data to a magnetic random access memory device having at least one of the present magnetic memory cells is also provided.
    Type: Grant
    Filed: December 23, 2016
    Date of Patent: July 25, 2017
    Assignee: International Business Machines Corporation
    Inventors: Guohan Hu, Luqiao Liu, Jonathan Z. Sun, Daniel C. Worledge
  • Patent number: 9647204
    Abstract: Magnetic memory devices having an antiferromagnetic reference layer based on Co and Ir are provided. In one aspect, a magnetic memory device includes a reference magnetic layer having multiple Co-containing layers oriented in a stack, wherein adjacent Co-containing layers in the stack are separated by an Ir-containing layer such that the adjacent Co-containing layers in the stack are anti-parallel coupled by the Ir-containing layer therebetween; and a free magnetic layer separated from the reference magnetic layer by a barrier layer. A method of writing data to a magnetic random access memory device having at least one of the present magnetic memory cells is also provided.
    Type: Grant
    Filed: December 5, 2014
    Date of Patent: May 9, 2017
    Assignee: International Business Machines Corporation
    Inventors: Guohan Hu, Luqiao Liu, Jonathan Z. Sun, Daniel C. Worledge
  • Publication number: 20170110655
    Abstract: Magnetic memory devices having an antiferromagnetic reference layer based on Co and Ir are provided. In one aspect, a magnetic memory device includes a reference magnetic layer having multiple Co-containing layers oriented in a stack, wherein adjacent Co-containing layers in the stack are separated by an Ir-containing layer such that the adjacent Co-containing layers in the stack are anti-parallel coupled by the Ir-containing layer therebetween; and a free magnetic layer separated from the reference magnetic layer by a barrier layer. A method of writing data to a magnetic random access memory device having at least one of the present magnetic memory cells is also provided.
    Type: Application
    Filed: December 23, 2016
    Publication date: April 20, 2017
    Inventors: Guohan Hu, Luqiao Liu, Jonathan Z. Sun, Daniel C. Worledge
  • Publication number: 20170069365
    Abstract: 3-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including non-volatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer.
    Type: Application
    Filed: November 21, 2016
    Publication date: March 9, 2017
    Inventors: Robert A Buhrman, Daniel C Ralph, Chi-Feng Pai, Luqiao Liu
  • Patent number: 9576631
    Abstract: An ST-MRAM structure, a method for fabricating the ST-MRAM structure and a method for operating an ST-MRAM device that results from the ST-MRAM structure each utilize a spin Hall effect base layer that contacts a magnetic free layer and effects a magnetic moment switching within the magnetic free layer as a result of a lateral switching current within the spin Hall effect base layer. This resulting ST-MRAM device uses an independent sense current and sense voltage through a magnetoresistive stack that includes a pinned layer, a non-magnetic spacer layer and the magnetic free layer which contacts the spin Hall effect base layer. Desirable non-magnetic conductor materials for the spin Hall effect base layer include certain types of tantalum materials and tungsten materials that have a spin diffusion length no greater than about five times the thickness of the spin Hall effect base layer and a spin Hall angle at least about 0.05.
    Type: Grant
    Filed: August 10, 2015
    Date of Patent: February 21, 2017
    Assignee: Cornell University
    Inventors: Robert A. Buhrman, Luqiao Liu, Daniel C. Ralph, Chi-Feng Pai
  • Patent number: 9502087
    Abstract: 3-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including non-volatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer.
    Type: Grant
    Filed: December 31, 2015
    Date of Patent: November 22, 2016
    Assignee: CORNELL UNIVERSITY
    Inventors: Robert A. Buhrman, Daniel C. Ralph, Chi-Feng Pai, Luqiao Liu
  • Publication number: 20160196860
    Abstract: 3-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including non-volatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer.
    Type: Application
    Filed: December 31, 2015
    Publication date: July 7, 2016
    Inventors: Robert A. Buhrman, Daniel C. Ralph, Chi-Feng Pai, Luqiao Liu
  • Publication number: 20160163966
    Abstract: Magnetic memory devices having an antiferromagnetic reference layer based on Co and Ir are provided. In one aspect, a magnetic memory device includes a reference magnetic layer having multiple Co-containing layers oriented in a stack, wherein adjacent Co-containing layers in the stack are separated by an Ir-containing layer such that the adjacent Co-containing layers in the stack are anti-parallel coupled by the Ir-containing layer therebetween; and a free magnetic layer separated from the reference magnetic layer by a barrier layer. A method of writing data to a magnetic random access memory device having at least one of the present magnetic memory cells is also provided.
    Type: Application
    Filed: December 5, 2014
    Publication date: June 9, 2016
    Inventors: Guohan Hu, Luqiao Liu, Jonathan Z. Sun, Daniel C. Worledge
  • Patent number: 9269415
    Abstract: Embodiments are directed to using an anomalous hall effect (AHE) or a polarized spin hall effect (PSHE) to switch a magnetic moment of a free layer having perpendicular magnetic anisotropy (PMA). AHE/PSHE includes materials with spontaneous magnetic moment. Thus, the spin orientation generated by AHE/PSHE not only depends upon the geometrical orientation, but also on the magnetic moment orientation of the AHE/PSHE material. Therefore, out-of-plane polarized spins are injected into the magnetic free layer, and the corresponding spin current switches the magnetic moment of a magnetic free layer with PMA through the anti-damping mechanism. In some embodiments, an asymmetric bottom lead may be used, such that a tunneling current flows toward one side after it leaves the free layer.
    Type: Grant
    Filed: September 18, 2014
    Date of Patent: February 23, 2016
    Assignee: International Business Machines Corporation
    Inventors: Luqiao Liu, Jonathan Z. Sun
  • Patent number: 9230626
    Abstract: 3-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including non-volatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer.
    Type: Grant
    Filed: August 6, 2013
    Date of Patent: January 5, 2016
    Assignee: CORNELL UNIVERSITY
    Inventors: Robert A. Buhrman, Daniel C. Ralph, Chi-Feng Pai, Luqiao Liu
  • Publication number: 20150348606
    Abstract: An ST-MRAM structure, a method for fabricating the ST-MRAM structure and a method for operating an ST-MRAM device that results from the ST-MRAM structure each utilize a spin Hall effect base layer that contacts a magnetic free layer and effects a magnetic moment switching within the magnetic free layer as a result of a lateral switching current within the spin Hall effect base layer. This resulting ST-MRAM device uses an independent sense current and sense voltage through a magnetoresistive stack that includes a pinned layer, a non-magnetic spacer layer and the magnetic free layer which contacts the spin Hall effect base layer. Desirable non-magnetic conductor materials for the spin Hall effect base layer include certain types of tantalum materials and tungsten materials that have a spin diffusion length no greater than about five times the thickness of the spin Hall effect base layer and a spin Hall angle at least about 0.05.
    Type: Application
    Filed: August 10, 2015
    Publication date: December 3, 2015
    Inventors: Robert A. Buhrman, Luqiao Liu, Daniel C. Ralph, Chi-Feng Pai
  • Patent number: 9105832
    Abstract: An ST-MRAM structure, a method for fabricating the ST-MRAM structure and a method for operating an ST-MRAM device that results from the ST-MRAM structure each utilize a spin Hall effect base layer that contacts a magnetic free layer and effects a magnetic moment switching within the magnetic free layer as a result of a lateral switching current within the spin Hall effect base layer. This resulting ST-MRAM device uses an independent sense current and sense voltage through a magnetoresistive stack that includes a pinned layer, a non-magnetic spacer layer and the magnetic free layer which contacts the spin Hall effect base layer. Desirable non-magnetic conductor materials for the spin Hall effect base layer include certain types of tantalum materials and tungsten materials that have a spin diffusion length no greater than about five times the thickness of the spin Hall effect base layer and a spin Hall angle at least about 0.05.
    Type: Grant
    Filed: August 17, 2012
    Date of Patent: August 11, 2015
    Assignee: Cornell University
    Inventors: Robert A. Buhrman, Luqiao Liu, Daniel C. Ralph, Chi-Feng Pai
  • Publication number: 20150200003
    Abstract: 3-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including non-volatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer.
    Type: Application
    Filed: August 6, 2013
    Publication date: July 16, 2015
    Inventors: Robert A. Buhrman, Daniel C. Ralph, Chi-Feng Pai, Luqiao Liu
  • Patent number: 8896041
    Abstract: Embodiments are directed to providing a spin hall effect (SHE) assisted spin transfer torque magnetic random access memory (STT-MRAM) device by coupling a magnetic tunnel junction (MTJ) to a SHE material, and coupling the SHE material to a transistor. Embodiments are directed to a spin transfer torque magnetic random access memory (STT-MRAM) device comprising: a magnetic tunnel junction (MTJ) coupled to a spin hall effect (SHE) material, and a transistor coupled to the SHE material.
    Type: Grant
    Filed: August 15, 2013
    Date of Patent: November 25, 2014
    Assignee: International Business Machines Corporation
    Inventors: John K. De Brosse, Luqiao Liu, Daniel Worledge
  • Patent number: 8889433
    Abstract: Embodiments are directed to providing a spin hall effect (SHE) assisted spin transfer torque magnetic random access memory (STT-MRAM) device by coupling a magnetic tunnel junction (MTJ) to a SHE material, and coupling the SHE material to a transistor. Embodiments are directed to a spin transfer torque magnetic random access memory (STT-MRAM) device comprising: a magnetic tunnel junction (MTJ) coupled to a spin hall effect (SHE) material, and a transistor coupled to the SHE material.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: November 18, 2014
    Assignee: International Business Machines Corporation
    Inventors: John K. De Brosse, Luqiao Liu, Daniel Worledge