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).
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Patent number: 10534579Abstract: 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: GrantFiled: September 28, 2018Date of Patent: January 14, 2020Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Patrick M. Braganca, Jordan A. Katine, Yang Li, Neil L. Robertson, Qingbo Wang, Haiwen Xi
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Patent number: 10490601Abstract: 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: GrantFiled: August 23, 2017Date of Patent: November 26, 2019Assignee: Western Digital Technologies, Inc.Inventors: Patrick M. Braganca, Hsin-Wei Tseng, Lei Wan
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Patent number: 10290338Abstract: 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: GrantFiled: December 18, 2017Date of Patent: May 14, 2019Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Patrick M. Braganca, John C. Read
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Patent number: 10276782Abstract: 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: GrantFiled: October 6, 2016Date of Patent: April 30, 2019Assignee: Western Digital Technologies, Inc.Inventors: Patrick M. Braganca, Andrei Gustavo Fidelis Garcia
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Patent number: 10269400Abstract: 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: GrantFiled: September 6, 2017Date of Patent: April 23, 2019Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Patrick M. Braganca, John C. Read
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Publication number: 20190034167Abstract: 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: ApplicationFiled: September 28, 2018Publication date: January 31, 2019Applicant: Western Digital Technologies, Inc.Inventors: Patrick M. Braganca, Jordan A. Katine, Yang Li, Neil L. Robertson, Qingbo Wang, Haiwen Xi
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Patent number: 10175948Abstract: 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: GrantFiled: September 6, 2016Date of Patent: January 8, 2019Assignee: Western Digital Technologies, Inc.Inventors: Patrick M. Braganca, Jordan A. Katine, Yang Li, Neil L. Robertson, Qingbo Wang, Haiwen Xi
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Publication number: 20180108391Abstract: 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: ApplicationFiled: December 18, 2017Publication date: April 19, 2018Inventors: Patrick M. BRAGANCA, John C. READ
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Publication number: 20170372763Abstract: 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: ApplicationFiled: September 6, 2017Publication date: December 28, 2017Inventors: Patrick M. BRAGANCA, John C. READ
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Patent number: 9852782Abstract: 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: GrantFiled: August 31, 2015Date of Patent: December 26, 2017Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Patrick M. Braganca, John C. Read
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Publication number: 20170352702Abstract: 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: ApplicationFiled: August 23, 2017Publication date: December 7, 2017Inventors: Patrick M. Braganca, Hsin-Wei Tseng, Lei Wan
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Patent number: 9837602Abstract: 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: GrantFiled: December 16, 2015Date of Patent: December 5, 2017Assignee: Western Digital Technologies, Inc.Inventor: Patrick M. Braganca
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Patent number: 9768229Abstract: 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: GrantFiled: October 22, 2015Date of Patent: September 19, 2017Assignee: Western Digital Technologies, Inc.Inventors: Patrick M. Braganca, Hsin-Wei Tseng, Lei Wan
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Publication number: 20170221540Abstract: 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: ApplicationFiled: January 28, 2016Publication date: August 3, 2017Inventors: Daniel BEDAU, Patrick M. BRAGANCA, Kurt Allan RUBIN
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Patent number: 9721636Abstract: 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: GrantFiled: January 28, 2016Date of Patent: August 1, 2017Assignee: Western Digital Technologies, Inc.Inventors: Daniel Bedau, Patrick M. Braganca, Kurt Allan Rubin
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Publication number: 20170179372Abstract: 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: ApplicationFiled: December 16, 2015Publication date: June 22, 2017Inventor: Patrick M. BRAGANCA
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Publication number: 20170117323Abstract: 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: ApplicationFiled: October 22, 2015Publication date: April 27, 2017Inventors: Patrick M. BRAGANCA, Hsin-Wei TSENG, Lei WAN
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Publication number: 20170117027Abstract: 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: ApplicationFiled: October 21, 2015Publication date: April 27, 2017Inventors: Patrick M. BRAGANCA, Lei WAN
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Publication number: 20170092844Abstract: 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: ApplicationFiled: October 6, 2016Publication date: March 30, 2017Inventors: Patrick M. BRAGANCA, Andrei Gustavo Fidelis GARCIA
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Publication number: 20170084818Abstract: 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: ApplicationFiled: September 18, 2015Publication date: March 23, 2017Applicant: HGST Netherlands B.V.Inventors: Patrick M. BRAGANCA, Luis CARGNINI, Jordan A. KATINE, Hsin-Wei TSENG