Patents by Inventor Patrick M. Braganca

Patrick M. Braganca 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).

  • Patent number: 10534579
    Abstract: A system according to one embodiment includes a pinned layer; a spacer layer above the pinned layer; a free layer above the spacer layer; a heating device, for heating the free layer to induce a paramagnetic thermal instability in the free layer whereby a magnetization of the free layer randomly switches between different detectable magnetic states upon heating thereof; and a magnetoresistance detection circuit for detecting an instantaneous magnetic state of the free layer.
    Type: Grant
    Filed: September 28, 2018
    Date of Patent: January 14, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Patrick M. Braganca, Jordan A. Katine, Yang Li, Neil L. Robertson, Qingbo Wang, Haiwen Xi
  • Patent number: 10490601
    Abstract: Embodiments of the present disclosure generally relate to data storage and computer memory systems, and more particularly, to a SOT-MRAM chip architecture. The SOT-MRAM chip architecture includes a plurality of leads, a plurality of memory cells, and a plurality of transistors. The leads may be made of a material having large spin-orbit coupling strength and high electrical resistivity. Each lead of the plurality of leads may include a plurality of first portions and a plurality of second portions distinct from the first portions. The electrical resistivity of the second portions is less than that of the first portions, so the total electrical resistivity of the lead is reduced, leading to improved power efficiency and signal to noise ratio.
    Type: Grant
    Filed: August 23, 2017
    Date of Patent: November 26, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Patrick M. Braganca, Hsin-Wei Tseng, Lei Wan
  • Patent number: 10290338
    Abstract: Embodiments disclosed herein generally relate to a multilayer magnetic device, and specifically to a spin-torque transfer magnetoresistive random access memory (STT-MRAM) device which provides for a reduction in the amount of current required for switching individual bits. As such, a polarizing reference layer consisting of a synthetic antiferromagnet (SAF) structure with an in-plane magnetized ferromagnet film indirectly exchange coupled to a magnetic film with perpendicular magnetic anisotropy (PMA) is disclosed. By tuning the exchange coupling strength and the PMA, the layers of the SAF may both be canted such that either may be used as a tilted polarizer for either an in-plane free layer or a free layer with PMA.
    Type: Grant
    Filed: December 18, 2017
    Date of Patent: May 14, 2019
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Patrick M. Braganca, John C. Read
  • Patent number: 10276782
    Abstract: The present disclosure generally relates to SHE-MRAM memory cells. A memory cell array comprises one or more memory cells, wherein each of the one or more memory cells comprises a gate electrode, an insulating layer, a spin orbit material electrode, a MTJ, and a top electrode parallel to the gate electrode. The gate electrode and the top electrode are perpendicular to the spin orbit material electrode. By applying a voltage to the gate electrode, passing a current along the spin orbit material electrode, and utilizing Rashba and/or spin Hall effects, writability of select memory cells is enhanced, allowing for individual memory cells to be written upon without disturbing neighboring memory cells. Additionally, Rashba and/or spin Hall effects in neighboring memory cells may be suppressed to ensure only the selected memory cell is written.
    Type: Grant
    Filed: October 6, 2016
    Date of Patent: April 30, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Patrick M. Braganca, Andrei Gustavo Fidelis Garcia
  • Patent number: 10269400
    Abstract: Embodiments disclosed herein generally relate to a multilayer magnetic device, and specifically to a spin-torque transfer magnetoresistive random access memory (STT-MRAM) device which provides for a reduction in the amount of current required for switching individual bits. As such, a polarizing reference layer consisting of a synthetic antiferromagnet (SAF) structure with an in-plane magnetized ferromagnet film indirectly exchange coupled to a magnetic film with perpendicular magnetic anisotropy (PMA) is disclosed. By tuning the exchange coupling strength and the PMA, the layers of the SAF may both be canted such that either may be used as a tilted polarizer for either an in-plane free layer or a free layer with PMA.
    Type: Grant
    Filed: September 6, 2017
    Date of Patent: April 23, 2019
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Patrick M. Braganca, John C. Read
  • Publication number: 20190034167
    Abstract: A system according to one embodiment includes a pinned layer; a spacer layer above the pinned layer; a free layer above the spacer layer; a heating device, for heating the free layer to induce a paramagnetic thermal instability in the free layer whereby a magnetization of the free layer randomly switches between different detectable magnetic states upon heating thereof; and a magnetoresistance detection circuit for detecting an instantaneous magnetic state of the free layer.
    Type: Application
    Filed: September 28, 2018
    Publication date: January 31, 2019
    Applicant: Western Digital Technologies, Inc.
    Inventors: Patrick M. Braganca, Jordan A. Katine, Yang Li, Neil L. Robertson, Qingbo Wang, Haiwen Xi
  • Patent number: 10175948
    Abstract: A system according to one embodiment includes a pinned layer; a spacer layer above the pinned layer; a free layer above the spacer layer; a heating device, for heating the free layer to induce a paramagnetic thermal instability in the free layer whereby a magnetization of the free layer randomly switches between different detectable magnetic states upon heating thereof; and a magnetoresistance detection circuit for detecting an instantaneous magnetic state of the free layer.
    Type: Grant
    Filed: September 6, 2016
    Date of Patent: January 8, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Patrick M. Braganca, Jordan A. Katine, Yang Li, Neil L. Robertson, Qingbo Wang, Haiwen Xi
  • Publication number: 20180108391
    Abstract: Embodiments disclosed herein generally relate to a multilayer magnetic device, and specifically to a spin-torque transfer magnetoresistive random access memory (STT-MRAM) device which provides for a reduction in the amount of current required for switching individual bits. As such, a polarizing reference layer consisting of a synthetic antiferromagnet (SAF) structure with an in-plane magnetized ferromagnet film indirectly exchange coupled to a magnetic film with perpendicular magnetic anisotropy (PMA) is disclosed. By tuning the exchange coupling strength and the PMA, the layers of the SAF may both be canted such that either may be used as a tilted polarizer for either an in-plane free layer or a free layer with PMA.
    Type: Application
    Filed: December 18, 2017
    Publication date: April 19, 2018
    Inventors: Patrick M. BRAGANCA, John C. READ
  • Publication number: 20170372763
    Abstract: Embodiments disclosed herein generally relate to a multilayer magnetic device, and specifically to a spin-torque transfer magnetoresistive random access memory (STT-MRAM) device which provides for a reduction in the amount of current required for switching individual bits. As such, a polarizing reference layer consisting of a synthetic antiferromagnet (SAF) structure with an in-plane magnetized ferromagnet film indirectly exchange coupled to a magnetic film with perpendicular magnetic anisotropy (PMA) is disclosed. By tuning the exchange coupling strength and the PMA, the layers of the SAF may both be canted such that either may be used as a tilted polarizer for either an in-plane free layer or a free layer with PMA.
    Type: Application
    Filed: September 6, 2017
    Publication date: December 28, 2017
    Inventors: Patrick M. BRAGANCA, John C. READ
  • Patent number: 9852782
    Abstract: Embodiments disclosed herein generally relate to a multilayer magnetic device, and specifically to a spin-torque transfer magnetoresistive random access memory (STT-MRAM) device which provides for a reduction in the amount of current required for switching individual bits. As such, a polarizing reference layer consisting of a synthetic antiferromagnet (SAF) structure with an in-plane magnetized ferromagnet film indirectly exchange coupled to a magnetic film with perpendicular magnetic anisotropy (PMA) is disclosed. By tuning the exchange coupling strength and the PMA, the layers of the SAF may both be canted such that either may be used as a tilted polarizer for either an in-plane free layer or a free layer with PMA.
    Type: Grant
    Filed: August 31, 2015
    Date of Patent: December 26, 2017
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Patrick M. Braganca, John C. Read
  • Publication number: 20170352702
    Abstract: Embodiments of the present disclosure generally relate to data storage and computer memory systems, and more particularly, to a SOT-MRAM chip architecture. The SOT-MRAM chip architecture includes a plurality of leads, a plurality of memory cells, and a plurality of transistors. The leads may be made of a material having large spin-orbit coupling strength and high electrical resistivity. Each lead of the plurality of leads may include a plurality of first portions and a plurality of second portions distinct from the first portions. The electrical resistivity of the second portions is less than that of the first portions, so the total electrical resistivity of the lead is reduced, leading to improved power efficiency and signal to noise ratio.
    Type: Application
    Filed: August 23, 2017
    Publication date: December 7, 2017
    Inventors: Patrick M. Braganca, Hsin-Wei Tseng, Lei Wan
  • Patent number: 9837602
    Abstract: A method for a non-volatile memory cell; specifically, a spin orbit torque MRAM (SOT-MRAM) memory cell which reduces the current required to switch individual bits. The memory cell includes a first interconnect line having a first longitudinal axis, an elliptically shaped MTJ bit (“bit”) having a long axis, and a second interconnect line having a second longitudinal axis perpendicular to the first interconnect line. The bit includes a polarized free layer, a barrier layer, and a polarized reference layer with a magnetic moment pinned at an angle different from the long axis. By disposing the long axis at an angle relative to the first longitudinal axis and second longitudinal axis and the reference layer as described, and applying a voltage to the interconnect line, a non-zero equilibrium angle can be induced between the free layer and the spin current or the Rashba field resulting in more coherent switching dynamics.
    Type: Grant
    Filed: December 16, 2015
    Date of Patent: December 5, 2017
    Assignee: Western Digital Technologies, Inc.
    Inventor: Patrick M. Braganca
  • Patent number: 9768229
    Abstract: Embodiments of the present disclosure generally relate to data storage and computer memory systems, and more particularly, to a SOT-MRAM chip architecture. The SOT-MRAM chip architecture includes a plurality of leads, a plurality of memory cells, and a plurality of transistors. The leads may be made of a material having large spin-orbit coupling strength and high electrical resistivity. Each lead of the plurality of leads may include a plurality of first portions and a plurality of second portions distinct from the first portions. The electrical resistivity of the second portions is less than that of the first portions, so the total electrical resistivity of the lead is reduced, leading to improved power efficiency and signal to noise ratio.
    Type: Grant
    Filed: October 22, 2015
    Date of Patent: September 19, 2017
    Assignee: Western Digital Technologies, Inc.
    Inventors: Patrick M. Braganca, Hsin-Wei Tseng, Lei Wan
  • Publication number: 20170221540
    Abstract: A method and apparatus for controlled switching of a magnetoresistive random access memory device is disclosed herein. The method includes delivering a current to a magnetoresistive random access memory device, wherein the MRAM device is in a first state, measuring a voltage drop across the magnetoresistive random access memory device in real-time with a resistance detector, wherein a voltage drop beyond a threshold voltage equates to switching from a first state to a second state, the first state different from the second state, determining whether the MRAM device has switched from the first state to the second state, and stopping the current delivered to the magnetoresistive random access memory device.
    Type: Application
    Filed: January 28, 2016
    Publication date: August 3, 2017
    Inventors: Daniel BEDAU, Patrick M. BRAGANCA, Kurt Allan RUBIN
  • Patent number: 9721636
    Abstract: A method and apparatus for controlled switching of a magnetoresistive random access memory device is disclosed herein. The method includes delivering a current to a magnetoresistive random access memory device, wherein the MRAM device is in a first state, measuring a voltage drop across the magnetoresistive random access memory device in real-time with a resistance detector, wherein a voltage drop beyond a threshold voltage equates to switching from a first state to a second state, the first state different from the second state, determining whether the MRAM device has switched from the first state to the second state, and stopping the current delivered to the magnetoresistive random access memory device.
    Type: Grant
    Filed: January 28, 2016
    Date of Patent: August 1, 2017
    Assignee: Western Digital Technologies, Inc.
    Inventors: Daniel Bedau, Patrick M. Braganca, Kurt Allan Rubin
  • Publication number: 20170179372
    Abstract: A method for a non-volatile memory cell; specifically, a spin orbit torque MRAM (SOT-MRAM) memory cell which reduces the current required to switch individual bits. The memory cell includes a first interconnect line having a first longitudinal axis, an elliptically shaped MTJ bit (“bit”) having a long axis, and a second interconnect line having a second longitudinal axis perpendicular to the first interconnect line. The bit includes a polarized free layer, a barrier layer, and a polarized reference layer with a magnetic moment pinned at an angle different from the long axis. By disposing the long axis at an angle relative to the first longitudinal axis and second longitudinal axis and the reference layer as described, and applying a voltage to the interconnect line, a non-zero equilibrium angle can be induced between the free layer and the spin current or the Rashba field resulting in more coherent switching dynamics.
    Type: Application
    Filed: December 16, 2015
    Publication date: June 22, 2017
    Inventor: Patrick M. BRAGANCA
  • Publication number: 20170117027
    Abstract: Embodiments of the present disclosure generally relate to data storage and computer memory systems, and more particularly, to a SOT-MRAM cell and chip architecture. The SOT-MRAM chip architecture includes a memory cell array having a plurality of first leads, a plurality of second leads, and a plurality of memory cells. Each memory cell of the plurality of memory cells includes a MTJ and a selector element. These SOT-MRAM cells eliminate the need to pass large currents through the barrier layer of the MTJ and the selector element eliminates the large transistors usually required for selecting a single memory cell without disturbing neighboring memory cells.
    Type: Application
    Filed: October 21, 2015
    Publication date: April 27, 2017
    Inventors: Patrick M. BRAGANCA, Lei WAN
  • Publication number: 20170117323
    Abstract: Embodiments of the present disclosure generally relate to data storage and computer memory systems, and more particularly, to a SOT-MRAM chip architecture. The SOT-MRAM chip architecture includes a plurality of leads, a plurality of memory cells, and a plurality of transistors. The leads may be made of a material having large spin-orbit coupling strength and high electrical resistivity. Each lead of the plurality of leads may include a plurality of first portions and a plurality of second portions distinct from the first portions. The electrical resistivity of the second portions is less than that of the first portions, so the total electrical resistivity of the lead is reduced, leading to improved power efficiency and signal to noise ratio.
    Type: Application
    Filed: October 22, 2015
    Publication date: April 27, 2017
    Inventors: Patrick M. BRAGANCA, Hsin-Wei TSENG, Lei WAN
  • Publication number: 20170092844
    Abstract: The present disclosure generally relates to SHE-MRAM memory cells. A memory cell array comprises one or more memory cells, wherein each of the one or more memory cells comprises a gate electrode, an insulating layer, a spin orbit material electrode, a MTJ, and a top electrode parallel to the gate electrode. The gate electrode and the top electrode are perpendicular to the spin orbit material electrode. By applying a voltage to the gate electrode, passing a current along the spin orbit material electrode, and utilizing Rashba and/or spin Hall effects, writability of select memory cells is enhanced, allowing for individual memory cells to be written upon without disturbing neighboring memory cells. Additionally, Rashba and/or spin Hall effects in neighboring memory cells may be suppressed to ensure only the selected memory cell is written.
    Type: Application
    Filed: October 6, 2016
    Publication date: March 30, 2017
    Inventors: Patrick M. BRAGANCA, Andrei Gustavo Fidelis GARCIA
  • Publication number: 20170084818
    Abstract: The present disclosure generally relates to spin-torque-transfer magnetoresistive random access memory (STT-MRAM) memory cells. In the magnetic tunnel junction (MTJ) of the STT-MRAM memory cell, a 1 nm thick barrier layer having a triclinic crystalline structure is doped with B, N, or C. By applying a positive voltage to the MTJ, the magnetic state of the free layer of the MTJ may be switched. By increasing the voltage applied to the MTJ, the MTJ may change to operate as a ReRAM memory cell, and the crystalline structure of the barrier layer may switch to monoclinic. Before reaching the breakdown voltage, a negative voltage may be applied to the MTJ to switch the crystalline structure of the barrier layer back to triclinic. Once the negative voltage is applied and the crystalline structure of the barrier layer is changed back to triclinic, the MTJ may function as a STT-MRAM cell once again.
    Type: Application
    Filed: September 18, 2015
    Publication date: March 23, 2017
    Applicant: HGST Netherlands B.V.
    Inventors: Patrick M. BRAGANCA, Luis CARGNINI, Jordan A. KATINE, Hsin-Wei TSENG