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Search Publications by: Mark D. Stiles (Fed)

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Displaying 26 - 50 of 198

Transport dynamics in a high-brightness magneto-optical-trap Li ion source

September 15, 2020
Author(s)
Jamie Gardner, William R. McGehee, Mark D. Stiles, Jabez J. McClelland
Laser-cooled gases offer an alternative to tip-based methods for generating high brightness ions for focused ion beam applications. These sources produce ions by photoionization of ultracold neutral atoms, where the narrow velocity distribution associated

Manipulation of Coupling and Magnon Transport in Magnetic Metal-Insulator Hybrid Structures

June 15, 2020
Author(s)
Yabin Fan, Patrick Quarterman, Joseph Finley, Jiahao Han, Pengxiang Zhang, Justin T. Hou, Mark D. Stiles, Alexander Grutter, Luqiao Liu
Ferromagnetic metals and insulators are widely used for generation, control and detection of magnon spin signals. Most magnonic structures are based primarily on either magnetic insulators or ferromagnetic metals, while heterostructures integrating both of

Streaming Batch Gradient Tracking for Neural Network Training

April 3, 2020
Author(s)
Siyuan Huang, Brian D. Hoskins, Matthew W. Daniels, Mark D. Stiles, Gina C. Adam
Faster and more energy efficient hardware accelerators are critical for machine learning on very large datasets. The energy cost of performing vector-matrix multiplication and repeatedly moving neural network models in and out of memory motivates a search

Coherent spin pumping in a strongly coupled magnon-magnon hybrid system

March 17, 2020
Author(s)
Yi Li, Wei Cao, Vivek P. Amin, Zhizhi Zhang, Jonathan Gibbons, Joseph Sklenar, John Pearson, Paul M. Haney, Mark D. Stiles, William E. Bailey, Valentine Novosad, Axel Hoffmann, Wei Zhang
We have experimentally identified coherent spin pumping acting as a dampinglike coupling in the magnon-magnon hybrid modes of permalloy/yttrium iron garnet (Py/YIG) bilayers. Using broadband ferromagnetic resonance, an ''avoided crossing" is observed well

Energy-efficient stochastic computing with superparamagnetic tunnel junctions

March 5, 2020
Author(s)
Matthew W. Daniels, Advait Madhavan, Philippe Talatchian, Alice Mizrahi, Mark D. Stiles
Stochastic computing has been limited by the inaccuracies introduced by correlations between the pseudorandom bitstreams used in the calculation. We hybridize a stochastic version of magnetic tunnel junctions with basic CMOS logic gates to create a

Neuromorphic Spintronics

March 2, 2020
Author(s)
Julie Grollier, Damien Querlioz, Kerem Camsari, Karin Everschor-Sitte, Shunsuke Fukami, Mark D. Stiles

Role of non-linear data processing on speech recognition task in the framework of reservoir computing

January 15, 2020
Author(s)
Flavio Abreu Araujo, Mathieu Riou, Jacob Torrejon, Sumito Tsunegi, Damien Querlioz, K. Yakushiji, Akio Fukushima, Hitoshi Kubota, Shinji Yuasa, Mark D. Stiles, Julie Grollier
The reservoir computing neural network architecture is widely used to test hardware systems for neuromorphic computing. One of the preferred tasks for bench-marking such devices is automatic speech recognition (ASR). However, this task requires acoustic

Temporal pattern recognition with delayed feedback spin-torque nano-oscillators

August 23, 2019
Author(s)
Mathieu Riou, Jacob Torrejon, B. Garitaine, Flavio Abreu Araujo, Paolo Bortolotti, Vincent Cros, Sumito Tsunegi, K. Yakushiji, Akio Fukushima, Hitoshi Kubota, Shinji Yuasa, Damien Querlioz, Mark D. Stiles, Julie Grollier
The recent demonstration of neuromorphic computing with spin-torque nano-oscillators has opened a path to energy efficient data processing. The success of this demonstration hinged on the intrinsic short-term memory of the oscillators. In this study, we

Streaming Batch Eigenupdates for Hardware Neural Networks

August 6, 2019
Author(s)
Brian D. Hoskins, Matthew W. Daniels, Siyuan Huang, Advait Madhavan, Gina C. Adam, Nikolai B. Zhitenev, Jabez J. McClelland, Mark D. Stiles
Neuromorphic networks based on nanodevices, such as metal oxide memristors, phase change memories, and flash memory cells, have generated considerable interest for their increased energy efficiency and density in comparison to graphics processing units

Intrinsic spin currents in ferromagnets

June 24, 2019
Author(s)
Vivek P. Amin, Junwen Li, Mark D. Stiles, Paul M. Haney
First principles calculations show that electric fields applied to ferromagnets generate spin currents flowing perpendicularly to the electric field. Reduced symmetry in these ferromagnets enables a wide variety of such spin currents. However, the total

A Truth-Matrix View into Unary Computing

June 22, 2019
Author(s)
Advait Madhavan, Georgios Tzimpragos, Mark D. Stiles, Timothy Sherwood
Our community has been exploring Time-of-arrival based codes as a candidate for very low energy information processing. A ``space-time'' algebra has been recently proposed that captures the essential features of such a paradigm. In order to gain some

Scalable method to find the shortest path in a graph with circuits of memristors

December 14, 2018
Author(s)
Alice Mizrahi, thomas Marsh, Brian D. Hoskins, Mark D. Stiles
Finding the shortest path in a graph has applications to a wide range of optimization problems. However, algorithmic methods scale with the size of the graph in terms of time and energy. We propose a method to solve the shortest path problem using circuits

Interface-generated spin currents

September 26, 2018
Author(s)
Vivek P. Amin, Jan Zemen, Mark D. Stiles
Transport calculations based on ab-initio band structures reveal large interface-generated spin currents at Co/Pt, Co/Cu, and Pt/Cu interfaces. These spin currents are driven by in-plane electric fields but flow out-of-plane, and can have similar strengths

Spin-torque excitation of perpendicular standing spin waves in coupled YIG/Co heterostructures

March 23, 2018
Author(s)
Stefan Klinger, Vivek P. Amin, Stephan Gepraegs, Kathrin Ganzhorn, Hannes Maier-Flaig, Matthias Althammer, Hans Huebl, Rudolf Gross, Robert McMichael, Mark D. Stiles, Sebastian Goennenwein, Mathias Weiler
We investigate yttrium iron garnet (YIG)/cobalt (Co) heterostructures using broadband ferromagnetic resonance (FMR). We observe an efficient excitation of perpendicular standing spin waves (PSSWs) in the YIG layer when the resonance frequencies of the YIG

Spin currents and spin-orbit torques in ferromagnetic trilayers

March 19, 2018
Author(s)
Seung-heon C. Baek, Vivek P. Amin, Young-Wan Oh, Gyungchoon Go, Seung-Jae Lee, Geun-Hee Lee, Kab-Jin Kim, Mark D. Stiles, Byong-Guk Park, Kyung Jin Lee
Spin current generation by the spin-orbit interaction is one of the central themes in condensed matter physics. The spin Hall effect, for instance, is a bulk spin-orbit coupling effect that converts a charge current to a spin current. A recent theory

Synthetic Antiferromagnetic Spintronics

March 2, 2018
Author(s)
Rembert Duine, Kyung Jin Lee, Stuart S. Parkin, Mark D. Stiles
Spintronic and nanomagnetic devices often derive their functionality from layers of different materials and the interfaces between them. This is especially true for synthetic antiferromagnets — two or more ferromagnetic layers aligned in antiparallel

Neuromorphic Computing through Time-Multiplexing with a Spin-Torque Nano-Oscillator

December 31, 2017
Author(s)
Mathieu Riou, Flavio Abreu Araujo, Jacob Torrejon, Sumito Tsunegi, Guru Khalsa, Damien Querlioz, Paolo Bortolotti, Vincent Cros, K. Yakushiji, Akio Fukushima, Hitoshi Kubota, Shinji Yuasa, Mark D. Stiles, Julie Grollier
Fabricating powerful neuromorphic chips the size of a thumb requires miniaturizing both hardware synapses and neurons. The challenge for neurons is to scale them down to submicrometer diameters while maintaining the properties that allow for reliable

Spin-orbit torques from interfacial spin-orbit coupling for various interfaces

September 26, 2017
Author(s)
Kyoung-Whan Kim, Kyung Jin Lee, Jairo Sinova, Hyun-Woo Lee, Mark D. Stiles
We use a perturbative approach to study the effects of interfacial spin-orbit coupling in magnetic multilayers by treating the two-dimensional Rashba model in a fully three-dimensional description of electron transport near an interface. This formalism

Advancements in Spintronics

September 25, 2017
Author(s)
Hideo Ohno, Mark D. Stiles, Bernard Dieny
Spintronics is the concept of using the spin degree of freedom to control electrical current to expand the capabilities of electronic devices. Over the last 10 years' considerable progress has been made. This progress has led to technologies ranging from

Neuromorphic computing with nanoscale spintronic oscillators

July 26, 2017
Author(s)
Jacob Torrejon, Mathieu Riou, Flavio Abreu Araujo, Sumito Tsunegi, Guru Khalsa, Damien Querlioz, Paolo Bortolotti, Vincent Cros, K. Yakushiji, Akio Fukushima, Hitoshi Kubota, Shinji Yuasa, Mark D. Stiles, Julie Grollier
In the brain, hundred billions of neurons develop rhythmic activities and interact to process information. Taking inspiration from this behavior to realize high density, low power neuromorphic computing requires coupling huge numbers of nanoscale non

Interface-induced phenomena in magnetism

June 5, 2017
Author(s)
Frances Hellman, Axel Hoffmann, Yaroslav Tserkovnyak, Geoffrey S. Beach, Eric E. Fullerton, C. Leighton, Allan H. MacDonald, Daniel C. Ralph, Dario A. Arena, Hermann A. Duerr, Peter Fischer, Julie Grollier, Joseph P. Heremans, Tomas Jungwirth, alexay V. Kimel, Bert Koopmans, Ilya N. Krivorotov, Steven J. May, Amanda K. Petford-Long, James M. Rondinelli, Nitin Samarth, Ivan K. Schuller, Andrei N. Slavin, Mark D. Stiles, Oleg Tchernyshyov, Andre Thiaville, Barry L. Zink
This article reviews static and dynamic interfacial effects in magnetism, focusing in particular on the current explosion in interfacially-driven magnetic effects and phenomena associated with spin-orbit coupling and intrinsic symmetry breaking at

Theory of Kondo suppression of spin polarization in nonlocal spin valves

March 7, 2017
Author(s)
Kyoung-Whan Kim, Liam O'Brien, Paul A. Crowell, C. Leighton, Mark D. Stiles
We theoretically analyze contributions from the Kondo effect to the spin polarization and spin diffusion length in all-metal nonlocal spin valves. Interdiffusion of ferromagnetic atoms into the normal metal layer creates a region in which Kondo physics

Perpendicular magnetic anisotropy of two-dimensional Rashba ferromagnets

November 3, 2016
Author(s)
Kyoung-Whan Kim, Kyung Jin Lee, Hyun-Woo Lee, Mark D. Stiles
We compute the magnetocrystalline anisotropy energy within two-dimensional Rashba models. For a free- electron Rashba model with infinite band width and infinite Brillouin zone, the anisotropy is exactly zero no matter how strong the Rashba coupling is