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Spin-Orbit-Torque Switching of Ferrimagnets by Terahertz electrical Pulses

Physical Review Applied 2022年第6期18卷 064012-064012页

作者： Hao Wu Deniz Turan Quanjun Pan Chao-Yao Yang Guanjie Wu Seyed Armin Razavi Bingqian Dai Nezih Tolga Yardimci Zhi Huang Jing Zhang Yi-Ying Chin Hong-Ji Lin Chih-Huang Lai Zongzhi Zhang Mona Jarrahi Kang L. Wang Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China Department of Electrical and Computer Engineering University of California Los Angeles California 90095 USA Department of Materials Science and Engineering National Tsing Hua University Hsinchu 30013 Taiwan Department of Materials Science and Engineering National Yang Ming Chiao Tung University Hsinchu 30013 Taiwan Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing Department of Optical Science and Engineering Fudan University Shanghai 200433 China Department of Physics National Chung Cheng University Chiayi 621301 Taiwan National Synchrotron Radiation Research Center Hsinchu 30076 Taiwan

In conventional spintronic devices, ferromagnetic materials are used, which have a magnetization dynamics timescale of around nanoseconds, setting a limit for the switching speed. Increasing the magnetization switching speed has been one of the major challenges for spintronic research. In this work we take advantage of the ultrafast magnetic dynamics in ferrimagnetic materials instead of ferromagnets, and we use femtosecond laser pulses and a plasmonic photoconductive switch to create THz electrical pulses for ferrimagnetic switching by spin-orbit torque. By anomalous Hall and magneto-optic Kerr effect (MOKE) measurement, we demonstrate the robust THz-electrical-pulse-driven magnetization switching of ferrimagnetic Gd−Fe−Co. The time-resolved MOKE shows more than 50-GHz magnetic resonance frequency of Gd−Fe−Co, indicating faster than 20-ps magnetic dynamics. X-ray magnetic circular dichroism demonstrates the antiferromagnetically coupled Fe and Gd sublattices. Our work provides a promising route to realize ultrafast operation speed for nonvolatile magnetic memory and logic applications.

关键词： Magnetization switching Magneto-optical effect Spin optoelectronics Spin-orbit torque Devices for digital logic, storage & processing Ferrimagnets Transition-metal rare-earth alloys Terahertz techniques

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FDM Printing: A Fabrication Method for Fluidic Soft Circuits?

FDM Printing: A Fabrication Method for Fluidic Soft Circuits...

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IEEE International Conference on Soft Robotics (RoboSoft)

作者： Savita V. Kendre Lehong Wang Ethan Wilke Nicholas Pacheco Loris Fichera Markus P. Nemitz Department of Robotics Engineering Worcester Polytechnic Institute Worcester MA USA Department of Computer Science Worcester Polytechnic Institute Worcester MA USA Department of Biomedical Engineering Worcester Polytechnic Institute Worcester MA USA Department of Mechanical and Materials Engineering Worcester Polytechnic Institute Worcester MA USA Department of Electrical and Computer Engineering Worcester Polytechnic Institute Worcester MA USA

Existing fluidic soft logic gates for controlling soft robots typically depend on labor-intensive manual fabrication or costly printing methods. In our research, we utilize Fused Deposition Modeling to create fully 3D-printed fluidic logic gates, fabricating a valve from thermoplastic polyurethane. We investigate the 3D printing of tubing and introduce a novel extrusion nozzle for tubing production. Our approach significantly reduces the production time for soft fluidic valves from 27 hours using replica molding to 3 hours with FDM printing. We apply our 3D-printed valve to develop optimized XOR gates and D-latch circuits, presenting a rapid and cost-effective fabrication method for fluidic logic gates that aims to make fluidic circuitry more accessible to the soft robotics community.

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Total variation superiorized conjugate gradient method for image reconstruction

arXiv

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arXiv 2017年

作者： Zibetti, Marcelo V. W. Lin, Chuan Herman, Gabor T. Graduate Program in Electrical Engineering and Computer Science Federal University of Technology - Paraná Curitiba80230-901 Brazil School of Electrical Engineering Southwest Jiaotong University Chengdu Sichuan610031 China Department of Computer Science Graduate Center City University of New York New YorkNY10016 United States

The conjugate gradient (CG) method is commonly used for the relatively-rapid solution of least squares problems. In image reconstruction, the problem can be ill-posed and also contaminated by noise;due to this, approaches such as regularization should be utilized. Total variation (TV) is a useful regularization penalty, frequently utilized in image reconstruction for generating images with sharp edges. When a non-quadratic norm is selected for regularization, as is the case for TV, then it is no longer possible to use CG. Nonlinear CG is an alternative, but it does not share the efficiency that CG shows with least squares and methods such as fast iterative shrinkage-thresholding algorithms (FISTA) are preferred for problems with TV norm. A different approach to including prior information is superiorization. In this paper it is shown that the conjugate gradient method can be superiorized. Five different CG variants are proposed, including preconditioned CG. The CG methods superiorized by the total variation norm are presented and their performance in image reconstruction is demonstrated. It is illustrated that some of the proposed variants of the superiorized CG method can produce reconstructions of superior quality to those produced by FISTA and in less computational time, due to the speed of the original CG for least squares problems. In the Appendix we examine the behavior of one of the superiorized CG methods (we call it S-CG);one of its input parameters is a positive number ". It is proved that, for any given " that is greater than the half-squared-residual for the least squares solution, S-CG terminates in a finite number of steps with an output for which the half-squared-residual is less than or equal to ". Importantly, it is also the case that the output will have a lower value of TV than what would be provided by unsuperiorized CG for the same value " of the half-squared residual. Copyright © 2017, The Authors. All rights reserved.

关键词： Conjugate gradient method

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Mid-wave to near-IR optoelectronic properties and epsilon-near-zero behavior in indium-doped cadmium oxide

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Physical Review materials 2021年第3期5卷 035202-035202页

作者： Angela Cleri John Tomko Kathleen Quiambao-Tomko Mario V. Imperatore Yanglin Zhu J. Ryan Nolen Joshua Nordlander Joshua D. Caldwell Zhiqiang Mao Noel C. Giebink Kyle P. Kelley Evan L. Runnerstrom Patrick E. Hopkins Jon-Paul Maria Penn State University Department of Materials Science and Engineering University Park Pennsylvania 16802 USA University of Virginia Department of Materials Science and Engineering Charlottesville Virginia 22904 USA Penn State University Department of Electrical Engineering University Park Pennsylvania 16802 USA Penn State University Department of Physics University Park Pennsylvania 16802 USA Vanderbilt University Interdisciplinary Materials Science Program Nashville Tennessee 37235 USA Oak Ridge National Laboratory Center for Nanophase Materials Science Oak Ridge Tennessee 37830 USA Army Research Office DEVCOM US Army Research Laboratory Research Triangle Park North Carolina 27709 USA University of Virginia Department of Mechanical and Aerospace Engineering Charlottesville Virginia 22904 USA University of Virginia Department of Physics Charlottesville Virginia 22904 USA

Indium-doped cadmium oxide (In:CdO) thin films exhibit tunable epsilon-near-zero (ENZ) modal frequencies across a wide spectral range, bridging the mid-wave and near-infrared (IR). In:CdO thin films are prepared by reactive cosputtering from metallic Cd and In targets using high-power impulse magnetron sputtering (HiPIMS) and radio frequency sputtering, respectively. Using this approach, CdO thin films with carrier concentrations ranging from 2.3×1019 to 4.0×1020cm–3 and mobilities ranging from 300 to 400cm2/Vs are readily achieved. UV-VIS absorption spectra are used to measure optical bandgap, revealing a Burstein-Moss shift of 0.58 eV across the doping range investigated. Optical measurements demonstrate the tunability of near-perfect plasmonic ENZ absorption across the mid-wave and into the near-IR spectral ranges by controlling the carrier concentration through doping, while tuning the film thickness for impedance matching. In comparison to other dopants that can be introduced to HiPIMS-deposited CdO, In offers the largest range of carrier concentrations while maintaining high mobility, thus allowing for the widest accessibility of the IR spectrum of a single plasmonic material grown by sputtering.

关键词： Plasmonics Reflectivity X-ray diffraction

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Effect of substrate temperature on magnetic properties of CoCrTa/Cr films

Effect of substrate temperature on magnetic properties of Co...

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International Conference on Magnetics (INTERMAG)

作者： Y. Shen D.E. Laughlin D.N. Lambeth Department of Metallurgical Engineering and Materials Science data Storage System Center Carnegie Mellon University Pittsburgh PA USA Department of Electrical and Computer Engineering data Storage System Center Carnegie Mellon University Pittsburgh PA USA

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Continuous Noninvasive Blood Pressure Measurement by Near Infra Red CCD Camera and Pulse Transmit Time Systems

Continuous Noninvasive Blood Pressure Measurement by Near In...

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International Conference on computer engineering and Applications (ICCEA)

作者： Petr Zurek Ondrej Krejcar Marek Penhaker Martin Cerny Robert Frischer Department of Measurement and Control Faculty of Electrical Engineering and Computer Science VSB-Technical University of Ostrava Ostrava Czech Republic Department of Automation and Computing in Metallurgy Faculty of Metallurgy and Materials Engineering Technical University of Ostrava Ostrava Czech Republic

ISBN: (纸本)9781424460793;9780769539829

The need of continuous blood pressure measurement is usable in wide spectrum of applications from physicians practice to home care applications. Many types of blood pressure measurement devices can be bought in electronics shops. All such devices are contact measurement devices which need to be in contact of human body (hand or foot mainly). Secondary they allow only one measurement per several minutes interval (typically ones in 10 minutes). Our goal is to develop a small device for noninvasive continuous measurement of blood pressure. This device must be a small battery powered embedded system which measure a blood pressure during a long time period and send this information remotely to operator's stations. We would like to try two systems of blood pressure monitoring. The first one is system with NIR CCD camera (Near Infra Red), which measure the wide changes of the blood vessels and the second one is system, which measure the pulse transmit time (PTT). At the end we can compare the systems and get information, which system will be a right way to obtain exact continuous blood pressure information.

关键词： Pulse measurements Blood pressure Pressure measurement Time measurement Charge coupled devices Charge-coupled image sensors Biomedical monitoring Battery charge measurement Humans Foot

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Effect of band anticrossing on the optical transitions in GaAs1−xNx/GaAs multiple quantum wells

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Physical Review B 2001年第8期64卷 085320-085320页

作者： J. Wu W. Shan W. Walukiewicz K. M. Yu J. W. Ager, III E. E. Haller H. P. Xin C. W. Tu Applied Science and Technology Graduate Group University of California Berkeley California 94720 Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California 94720 Department of Materials Sciences and Engineering University of California Berkeley California 94720 Department of Electrical and Computer Engineering University of California San Diego La Jolla California 92093

Interband transitions in GaAs1−xNx/GaAs multiple quantum wells were studied at room temperature by photomodulated reflectance spectroscopy as a function of well width (3–9 nm), the nitrogen concentration (0.012<x&...

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Body surface Laplacian mapping of ventricular depolarization from potential recordings in humans

Body surface Laplacian mapping of ventricular depolarization...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： M. O'Hara X. Yu N. Mehdi C. Schwartz D. Wu B. Avitall B. He Bioeng. Program Illinois Univ. Chicago IL USA Department of Electrical Engineering and Computer Science University of Illinois Chicago Bioengineering Program University of Illinois Chicago Department of Medicine University of Illinois Chicago

We investigated the feasibility of obtaining body surface Laplacian maps (BSLMs) from unipolar electrocardiographic recordings in humans. The overall pattern of the BSLMs during ventricular depolarization is reproducible for subjects examined and for multiple sets of maps within a single subject. Right and left ventricular activities are well resolved in the BSLMs over the anterior chest as compared with body surface potential maps (BSPMs). Our experimental results demonstrate the feasibility of performing body surface Laplacian electrocardiographic mapping from potential recordings. The effects of measurement noise and electrode position uncertainty on the Laplacian derivation were also evaluated by computer simulation.

关键词： Laplace equations Humans Electrodes Bioelectric phenomena Electric potential computer simulation Position measurement Noise measurement Signal processing Gaussian noise

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LED Lights with Hidden Intensity-Modulated Blue Channels Aiming for Enhanced Subconscious Visual Responses

IEEE Photonics Journal

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IEEE Photonics Journal 2017年第3期9卷 8201009页

作者： Vartanian, Garen Wong, Kwoon Y. Ku, Pei-Cheng Macromolecular Science and Engineering Graduate Program University of Michigan Ann ArborMI48109 United States Department of Ophthalmology and Visual Sciences University of Michigan Ann ArborMI48109 United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States

A new form of light-emitting diode (LED) light suitable for general illumination is proposed to enhance subconscious, nonimage-forming visual responses, which are essential to our well-being. Pulsing light has been shown to reduce photoreceptor adaptation and elicit stronger subconscious visual responses at an indoor illumination level. Using the silent substitution technique, a melanopsin-selective flicker can be added into white light. A linear optimization algorithm was developed to suppress any perceivable fluctuation of light intensity and colors of illuminated objects. Two examples of lights are given to illustrate the potential applications of the proposed multi-LED light for general illumination and therapeutic purposes. © 2009-2012 IEEE.

关键词： Light emitting diodes

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Growth studies of quantum cascade lasers with current-blocking structures

Growth studies of quantum cascade lasers with current-blocki...

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Quantum Electronics and Laser science Conference (QELS)

作者： Liwei Cheng Xiaoming Ji Fow-Sen Choa Zhijun Liu Claire F. Gmachl Jeny Fan Xiaojun Wang Rich Leavitt John Bruno John Bradshaw Department of Computer Science and Electrical Engineering University of Maryland Baltimore MD USA Department of Electrical Engineering and Princeton Institute for the Science and Technology of Materials (PRISM) Princeton University Princeton NJ USA AdTech Optics Inc. IA USA Maxion Technologies Inc. Hyattsville MD USA

Buried-heterosturcture regrowths have very significant impact on quantum-cascade-laser (QCL) threshold, output power, and reliability. We report detailed BH regrowth studies on QCLs along different crystal orientation... 详细信息

ISBN: (纸本)9781424435906

关键词： Quantum cascade lasers Waveguide lasers Semiconductor lasers Optical waveguides Semiconductor waveguides Quantum computing materials science and technology Power generation Temperature Telecommunications

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