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2020-10-14
Spin torque gate magnetic field sensor
Spin-orbit torque provides an efficient pathway to manipulate the magnetic state and magnetization dynamics of magnetic materials, which is crucial for energy-efficient operation of a variety of spintronic devices such as magnetic memory, logic, oscillator, and neuromorphic computing. Here, we describe and experimental...
2010.07158v1
2020-11-06
Picosecond Switching of Optomagnetic Tunnel Junctions
Perpendicular magnetic tunnel junctions are one of the building blocks for spintronic memories, which allow fast nonvolatile data access, offering substantial potentials to revolutionize the mainstream computing architecture. However, conventional switching mechanisms of such devices are fundamentally hindered by spin ...
2011.03612v1
2020-12-10
Observation of Magnetic Droplets in Magnetic Tunnel Junctions
Magnetic droplets, a class of highly non-linear magnetodynamical solitons, can be nucleated and stabilized in nanocontact spin-torque nano-oscillators where they greatly increase the microwave output power. Here, we experimentally demonstrate magnetic droplets in magnetic tunnel junctions (MTJs). The droplet nucleation...
2012.05596v1
2020-12-20
Creation of a Chiral Bobber Lattice in Helimagnet-Multilayer Heterostructures
A chiral bobber is a localized three-dimensional magnetization configuration, terminated by a singularity. Chiral bobbers coexist with magnetic skyrmions in chiral magnets, lending themselves to new types of skyrmion-complementary bits of information. However, the on-demand creation of bobbers, as well as their direct ...
2012.10924v1
2021-01-10
A Thermodynamic Core using Voltage-Controlled Spin-Orbit-Torque Magnetic Tunnel Junctions
We present a magnetic implementation of a thermodynamic computing fabric. Magnetic devices within computing cores harness thermodynamics through its voltage-controlled thermal stability; while the evolution of network states is guided by the spin-orbit-torque effect. We theoretically derive the dynamics of the cores an...
2101.03448v3
2021-04-07
Magnetic Reversal and Critical Current Transparency of CoFeB Superconductor-Ferromagnet-Superconductor Heterostructures
In this work, we show fundamental low temperature (T) magnetic and Ic responses of a magnetic Josephson Junction (MJJ) S/F/S heterostructure - Nb/ Co56Fe24B20 /Nb. The ultra-thin Co56Fe24B20 (CFB) films (0.6-1.3 nm) were deposited onto two separate buffer layers: 150 nm Nb/5 nm Cu and 150 nm Nb/ (1 nm Cu/0.5 nm Nb)6/1 ...
2104.03188v1
2021-06-22
Room And Cryogenic Temperature Behaviour of Magnetic Sensors Based on Gan/Si Single Saw Resonators
This work analyzes resonance frequency shift vs. the applied magnetic field strength for GHz operating GaN/Si SAW single resonators. Magnetostrictive elements (Ni and CoFeB) were deposited in the proximity of the interdigitated transducers (IDTs) of the resonators (A-type structures) and also over the IDTs, after cover...
2106.11605v1
2021-08-01
Terahertz charge and spin transport in metallic ferromagnets: the role of crystalline and magnetic order
We study the charge and spin dependent scattering in a set of CoFeB thin films whose crystalline order is systematically enhanced and controlled by annealing at increasingly higher temperatures. Terahertz conductivity measurements reveal that charge transport closely follows the development of the crystalline phase, wi...
2108.00456v1
2021-11-12
Fabrication of voltage gated spin Hall nano-oscillators
We demonstrate an optimized fabrication process for electric field (voltage gate) controlled nano-constriction spin Hall nano-oscillators (SHNOs), achieving feature sizes of <30 nm with easy to handle ma-N 2401 e-beam lithography negative tone resist. For the nanoscopic voltage gates, we utilize a two-step tilted ion b...
2111.06957v1
2021-11-26
Three-dimensional Resonant Magnetization Dynamics Unraveled by Time-Resolved Soft X-ray Laminography
The imaging of magneto-dynamical processes has been, so far, mostly a two-dimensional business, due to the constraints of the available experimental techniques. In this manuscript, building on the recent developments of soft X-ray magnetic laminography, we present an experimental setup where magneto-dynamical processes...
2111.13533v1
2022-01-11
Perpendicular magnetic tunnel junctions with multi-interface free layer
Future generations of magnetic random access memory demand magnetic tunnel junctions that can provide simultaneously high magnetoresistance, strong retention, low switching energy and small cell size below 10nm. Here we study perpendicular magnetic tunnel junctions with composite free layers where multiple ferromagnet/...
2201.03798v1
2022-04-06
Power transfer in magnetoelectric resonators
We derive an analytical model for the power transfer in a magnetoelectric film bulk acoustic resonator consisting of a piezoelectric--magnetostrictive bilayer. The model describes the dynamic magnetostrictive influence on the elastodynamics via an effective frequency-dependent stiffness constant. This allows for the ca...
2204.03072v2
2022-10-03
Voltage control of frequency, effective damping and threshold current in nano-constriction-based spin Hall nano-oscillators
Using micromagnetic simulations, we study the interplay between strongly voltage-controlled magnetic anisotropy (VCMA), $\Delta K = \pm$200 kJ/m$^3$, and gate width, $w=$ 10--400 nm, in voltage-gated W/CoFeB/MgO based nano-constriction spin Hall nano-oscillators. The VCMA modifies the local magnetic properties such tha...
2210.01042v1
2022-10-11
Thermally-generated spin current in the topological insulator Bi$_2$Se$_3$
We complete measurements of interconversions among the full triad of thermal gradients, charge currents, and spin currents in the topological insulator Bi$_2$Se$_3$ by quantifying the efficiency with which thermal gradients can generate transverse spin currents. We accomplish this by comparing the spin Nernst magneto-t...
2210.05636v1
2022-10-26
Perpendicular magnetic anisotropy, tunneling magnetoresistance and spin-transfer torque effect in magnetic tunnel junctions with Nb layers
Nb and its compounds are widely used in quantum computing due to their high superconducting transition temperatures and high critical fields. Devices that combine superconducting performance and spintronic non-volatility could deliver unique functionality. Here we report the study of magnetic tunnel junctions with Nb a...
2210.14969v1
2022-10-30
Interplay of symmetry-conserved tunneling, interfacial oxidation and perpendicular magnetic anisotropy in CoFeB/MgO-based junctions
The interfacial oxidation level and thermodynamic properties of the MgO-based perpendicular magnetic tunneling junctions are investigated. The symmetry-conserved tunneling effect depends sensitively on the MgO adatom energy during the RF sputtering, as well as the thermal stability of the structure during the post-grow...
2210.16734v1
2022-12-08
Acoustic-Driven Magnetic Skyrmion Motion
Magnetic skyrmions have great potential for developing novel spintronic devices. The electrical manipulation of skyrmions has mainly relied on current-induced spin-orbit torques. A recent theoretical model suggested that the skyrmions could be more efficiently manipulated by surface acoustic waves (SAW), an elastic wav...
2212.04049v1
2023-04-30
Specific features of g $\approx$ 4.3 EPR line behavior in magnetic nanogranular composites
Films of metal-insulator nanogranular composites M$_x$D$_{100-x}$ with different composition and percentage of metal and dielectric phases (M = Fe, Co, CoFeB; D = Al$_2$O$_3$, SiO$_2$, LiNbO$_3$; x $\approx$ 15-70 at.%) are investigated by magnetic resonance in a wide range of frequencies (f = 7-37 GHz) and temperature...
2305.00551v1
2023-05-16
Terahertz spin conductance probes of coherent and incoherent spin tunneling through MgO tunnel junctions
We study femtosecond spin currents through MgO tunneling barriers in CoFeB(2 nm)|MgO($d$)|Pt(2 nm) stacks by terahertz emission spectroscopy. To obtain transport information independent of extrinsic experimental factors, we determine the complex-valued spin conductance $\tilde{G}_d (\omega)$ of the MgO layer (thickness...
2305.09074v2
2023-05-18
Observation and enhancement of room temperature bilinear magnetoelectric resistance in sputtered topological semimetal Pt3Sn
Topological semimetal materials have become a research hotspot due to their intrinsic strong spin-orbit coupling which leads to large charge-to-spin conversion efficiency and novel transport behaviors. In this work, we have observed a bilinear magnetoelectric resistance (BMER) of up to 0.1 nm2A-1Oe-1 in a singlelayer o...
2305.10720v2
2023-07-07
Orbitronics: Light-induced Orbit Currents in Terahertz Emission Experiments
Orbitronics is based on the use of orbit currents as information carriers. Up to now, orbit currents were created from the conversion of charge or spin currents, and inversely, they could be converted back to charge or spin currents. Here we demonstrate that orbit currents can also be generated by femtosecond light pul...
2307.03490v1
2023-09-06
Shaping magnetization dynamics in a planar square dot by adjusting its surface anisotropy
A planar square dot is one of the simplest structures confined to three dimensions. Despite its geometrical simplicity, the description of the spin wave modes in this structure is not trivial due to the competition of dipolar and exchange interactions. An additional factor that makes this description challenging are th...
2309.02984v1
2023-09-22
Strongly Coupled Spin Waves and Surface Acoustic Waves at Room Temperature
Here, we report the observation of strong coupling between magnons and surface acoustic wave (SAW) phonons in a thin CoFeB film constructed in an on-chip SAW resonator by analyzing SAW phonon dispersion anticrossings. Our device design provides the tunability of the film thickness with a fixed phonon wavelength, which ...
2309.12690v1
2023-10-20
Visualization of skyrmion-superconducting vortex pairs in a chiral magnet-superconductor heterostructure
Magnetic skyrmions, the topological states possessing chiral magnetic structure with non-trivial topology, have been widely investigated as a promising candidate for spintronic devices. They can also couple with superconducting vortices to form skyrmion-vortex pairs, hosting Majorana zero mode which is a potential cand...
2310.13363v1
2023-10-26
On-chip all-electrical determination of the magnetoelastic coupling constant of magnetic heterostructures
We have developed an approach to determine the magnetoelastic coupling constant of magnetic layers in thin film heterostructures. The film is formed on a piezoelectric substrate between two interdigital transducers (IDT), a platform often used to construct a surface acoustic wave device. With the substrate piezoelectri...
2310.17215v1
2023-12-06
Large Non-Volatile Frequency Tuning of Spin Hall Nano-Oscillators using Circular Memristive Nano-Gates
Spin Hall nano oscillators (SHNOs) are promising candidates for neuromorphic computing due to their miniaturized dimensions, non-linearity, fast dynamics, and ability to synchronize in long chains and arrays. However, tuning the individual SHNOs in large chains/arrays, which is key to implementing synaptic control, has...
2312.03352v2
2008-05-16
The influence of intergranular interaction on the magnetization of the ensemble of oriented Stoner-Wohlfarth nanoparticles
We consider the influence of interparticle interaction on the magnetization reversal in the oriented Stoner-Wohlfarth nanoparticles ensemble. To do so, we solve a kinetic equation for the relaxation of the overall ensemble magnetization to its equilibrium value in some effective mean field. Latter field consists of ext...
0805.2463v3
2009-07-22
Quantized spin wave modes in magnetic tunnel junction nanopillars
We present an experimental and theoretical study of the magnetic field dependence of the mode frequency of thermally excited spin waves in rectangular shaped nanopillars of lateral sizes 60x100, 75x150, and 105x190 nm2, patterned from MgO-based magnetic tunnel junctions. The spin wave frequencies were measured using sp...
0907.3792v2
2014-09-02
Switching of Perpendicularly Polarized Nanomagnets with Spin Orbit Torque without an External Magnetic Field by Engineering a Tilted Anisotropy
Spin orbit torque (SOT) provides an efficient way of generating spin current that promises to significantly reduce the current required for switching nanomagnets. However, an in-plane current generated SOT cannot deterministically switch a perpendicularly polarized magnet due to symmetry reasons. On the other hand, per...
1409.0620v3
2015-10-13
Efficient metallic spintronic emitters of ultrabroadband terahertz radiation
Terahertz electromagnetic radiation is extremely useful for numerous applications such as imaging and spectroscopy. Therefore, it is highly desirable to have an efficient table-top emitter covering the 1-to-30-THz window whilst being driven by a low-cost, low-power femtosecond laser oscillator. So far, all solid-state ...
1510.03729v2
2016-07-22
The Spin Nernst effect in Tungsten
The spin Hall effect allows generation of spin current when charge current is passed along materials with large spin orbit coupling. It has been recently predicted that heat current in a non-magnetic metal can be converted into spin current via a process referred to as the spin Nernst effect. Here we report the observa...
1607.06594v2
2017-09-08
Observation of Magnetic Radial Vortex Nucleation in a Multilayer Stack with Tunable Anisotropy
Recently discovered exotic magnetic configurations, namely magnetic solitons appearing in the presence of bulk or interfacial Dzyaloshinskii-Moriya Interaction (i-DMI), have excited scientists to explore their potential applications in emerging spintronic technologies such as race-track magnetic memory, spin logic, rad...
1709.02876v1
2018-03-12
Electrical initialization of electron and nuclear spins in a single quantum dot at zero magnetic field
The emission of circularly polarized light from a single quantum dot relies on the injection of carriers with well-defined spin polarization. Here we demonstrate single dot electroluminescence (EL) with a circular polarization degree up to 35% at zero applied magnetic field. The injection of spin polarized electrons is...
1803.04309v1
2018-06-20
Current-induced modulation of interfacial Dzyaloshinskii-Moriya interaction
The Dzyaloshinskii-Moriya (DM) interaction is an antisymmetric exchange interaction that is responsible for the emergence of chiral magnetism. The origin of the DM interaction, however, remains to be identified albeit the large number of studies reported on related effects. It has been recently suggested that the DM in...
1806.07746v2
2018-06-25
Two-terminal spin-orbit torque magnetoresistive random access memory
Spin-transfer torque magnetoresistive random access memory (STT-MRAM) is an attractive alternative to current random access memory technologies due to its non-volatility, fast operation and high endurance. STT-MRAM does though have limitations including the stochastic nature of the STT-switching and a high critical swi...
1806.09713v2
2018-09-14
Femtosecond control of terahertz spin-charge conversion in ferromagnetic heterostructures
Employing electron spin instead of charge to develop spintronic devices holds the merits of low-power consumption in information technologies. Meanwhile, the demand for increasing speed in spintronics beyond current CMOS technology has further triggered intensive researches for ultrafast control of spins even up to unp...
1809.05391v2
2018-11-21
Strong Rashba-Edelstein Effect-Induced Spin-Orbit Torques in Monolayer Transition-Metal Dichalcogenide/Ferromagnet Bilayers
The electronic and optoelectronic properties of two dimensional materials have been extensively explored in graphene and layered transition metal dichalcogenides (TMDs). Spintronics in these two-dimensional materials could provide novel opportunities for future electronics, for example, efficient generation of spin cur...
1811.08583v1
2020-01-15
Nonreciprocal surface acoustic wave propagation via magneto-rotation coupling
One of the most fundamental forms of magnon-phonon interaction is an intrinsic property of magnetic materials, the "magnetoelastic coupling". This particular form of interaction has been the basis for describing magnetic materials and their strain related applications, where strain induces changes of internal magnetic ...
2001.05135v3
2020-01-15
Backward volume vs Damon-Eshbach: a travelling spin wave spectroscopy comparison
We compare the characteristics of electrically transduced Damon-Eshbach (DESWs) and backward volume (BVSWs) configurations within the same, 30 nm thick, ferromagnetic, CoFeB waveguide. Sub-micron U-shaped antennas are used to deliver the necessary in-plane and out-of-plane RF fields. We measure the spin-wave transmissi...
2001.05221v2
2021-07-20
Spin-wave dispersion measurement by variable-gap propagating spin-wave spectroscopy
Magnonics is seen nowadays as a candidate technology for energy-efficient data processing in classical and quantum systems. Pronounced nonlinearity, anisotropy of dispersion relations and phase degree of freedom of spin waves require advanced methodology for probing spin waves at room as well as at mK temperatures. Yet...
2107.09363v1
2017-03-18
Spin Based Biosensor with Hard Axis Assist for Enhanced Sensitivity
We demonstrate the influence of hard axis assist on an in-plane polarized nanomagnet layer to greatly enhance the sensitivity of a magnetic nano particle (MNP) based MTJ biosensor. The hard axis assist has been provided to the sensing layer in the forms of spin Hall Effect (SHE) induced spin injected torque and stress ...
1704.01555v1
2017-04-20
Coupled mode theory for the acoustic wave and spin wave interaction in the magphonic crystals: Propagating magnetoelastic waves
We have investigated co-directional and contra-directional couplings between spin wave and acoustic wave in one-dimensional periodic structure (magphonic crystal). The system consists of two ferromagnetic layers alternating in space. We have taken into consideration materials commonly used in magnonics: yttrium iron ga...
1704.06118v1
2018-07-17
Large anomalous Nernst effect in thin films of the Weyl semimetal Co2MnGa
The magneto-thermoelectric properties of Heusler compound thin films are very diverse. Here, we discuss the anomalous Nernst response of Co$_2$MnGa thin films. We systematically study the anomalous Nernst coefficient as a function of temperature, and we show that unlike the anomalous Hall effect, the anomalous Nernst e...
1807.06487v1
2019-01-05
Demonstration of a strain-mediated magnetoelectric write and read unit in a Co60Fe20B20/ Pb(Mg1/3Nb2/3)0.7Ti0.3O3 heterostructure
Taking advantage of the Magnetoelectric (ME) and its inverse effect, this article demonstrates strain-mediated magnetoelectric write and read operations simultaneously in Co60Fe20B20/ Pb(Mg1/3Nb2/3)0.7Ti0.3O3 heterostructures without using any symmetry breaking magnetic field at room temperature. By applying an externa...
1901.01368v1
2019-01-24
Topology-Dependent Brownian Gyromotion of a Single Skyrmion
Non-interacting particles exhibiting Brownian motion have been observed in many occasions of sciences, such as molecules suspended in liquids, optically trapped microbeads, and spin textures in magnetic materials. In particular, a detailed examination of Brownian motion of spin textures is important for designing therm...
1901.08206v2
2018-02-02
Spin wave emission by spin-orbit torque antennas
We study the generation of propagating spin waves in Ta/CoFeB waveguides by spin-orbit torque antennas and compare them to conventional inductive antennas. The spin-orbit torque was generated by a transverse microwave current across the magnetic waveguide. The detected spin wave signals for an in-plane magnetization ac...
1802.00861v2
2019-02-10
Evidence of Pure Spin-Current Generated by Spin Pumping in Interface Localized States in Hybrid Metal-Silicon-Metal Vertical Structures
Due to the difficulty to grow high quality semiconductors on ferromagnetic metals, the study of spin diffusion transport in Si was only limited to lateral geometry devices. In this work, by using ultra-high vacuum wafer-bonding technique, we have successfully fabricated metal semiconductor metal CoFeB/MgO/Si/Pt vertica...
1902.03652v1
2019-02-19
Generation and Hall effect of skyrmions enabled via using nonmagnetic point contacts
To enable functional skyrmion based spintronic devices, the controllable generation and manipulation of skyrmions is essential. While the generation of skyrmions by using a magnetic geometrical constriction has already been demonstrated, this approach is difficult to combine with a subsequent controlled manipulation of...
1902.06954v1
2020-04-05
Spin wave based tunable switch between superconducting flux qubits
Quantum computing hardware has received world-wide attention and made considerable progress recently. YIG thin film have spin wave (magnon) modes with low dissipation and reliable control for quantum information processing. However, the coherent coupling between a quantum device and YIG thin film has yet been demonstra...
2004.02156v1
2020-08-14
Spin-injection and spin-relaxation in p-doped InGaAs/GaAs quantum-dot spin light emitting diode at zero magnetic field
We report on efficient spin injection in p-doped InGaAs/GaAs quantum-dot (QD) spin light emitting diode (spin-LED) under zero applied magnetic field. A high degree of electroluminescence circular polarization (Pc) ~19% is measured in remanence up to 100K. This result is obtained thanks to the combination of a perpendic...
2008.06407v1
2020-08-17
Enhancement of spin Hall conductivity in W-Ta alloy
Generating pure spin currents via the spin Hall effect in heavy metals has been an active topic of research in the last decade. In order to reduce the energy required to efficiently switch neighbouring ferromagnetic layers for applications, one should not only increase the charge- to-spin conversion efficiency but also...
2008.07572v1
2016-02-08
External-Field-Free Spin Hall Switching of Perpendicular Magnetic Nanopillar with a Dipole-Coupled Composite Structure
Spin Hall effect (SHE) induced reversal of perpendicular magnetization has attracted significant interest, due to its potential to lead to low power memory and logic devices. However, the switching requires an assisted in-plane magnetic field, which hampers its practical applications. Here, we introduce a novel approac...
1603.09624v2
2017-02-16
Pumping laser excited spins through MgO barriers
We present a study of the tunnel magneto-Seebeck (TMS) effect in MgO based magnetic tunnel junctions (MTJs). The electrodes consist of CoFeB with in-plane magnetic anisotropy. The temperature gradients which generate a voltage across the MTJs layer stack are created using laser heating. Using this method, the temperatu...
1702.05038v1
2017-02-21
All-optical Detection of Spin Hall Angle in W/CoFeB/SiO2 Heterostructures by Varying Tungsten Layer Thickness
The development of advanced spintronics devices hinges on the efficient generation and utilization of pure spin current. In materials with large spin-orbit coupling, the spin Hall effect may convert charge current to pure spin current and a large conversion efficiency, which is quantified by spin Hall angle (SHA), is d...
1702.06258v1
2019-05-27
Unidirectional planar Hall voltages induced by surface acoustic waves in ferromagnetic thin films
The electromotive forces induced by surface acoustic waves (SAWs) are investigated in ferromagnetic thin films. CoFeB thin films deposited on LiNbO$_3$ substrates are patterned into Hall-bars to study the acoustoelectric transport properties of the device. The longitudinal and transverse dc voltages that develop in the...
1905.11224v1
2020-07-23
Electrical Detection of Light Helicity using a Quantum Dots based Hybrid Device at Zero Magnetic Field
Photon helicity-dependent photocurrent is measured at zero magnetic field on a device based on an ensemble of InGaAs/GaAs quantum dots that are embedded into a GaAs-based p-i-n diode. Our main goal is to take advantage of the long electron spin relaxation time expected in these nano-objects. In these experiments, no ex...
2007.12054v1
2020-12-02
Engineered magnetization and exchange stiffness in direct-write Co-Fe nanoelements
Media with engineered magnetization are essential building blocks in superconductivity, magnetism and magnon spintronics. However, the established thin-film and lithographic techniques insufficiently suit the realization of planar components with on-demand-tailored magnetization in the lateral dimension. Here, we demon...
2012.01481v1
2021-04-05
Analyser-free, intensity-based wide-field magneto-optical microscopy
In conventional Kerr- and Faraday microscopy the sample is illuminated with plane-polarised light and a magnetic domain contrast is generated by an analyser making use of the Kerr- or Faraday rotation. In this paper we demonstrate possibilities of analyser-free magneto-optical microscopy based on magnetisation-dependen...
2104.01831v2
2021-06-29
Spin Hall effect in a spin-1 chiral semimetal
Spin-1 chiral semimetal is a new state of quantum matter hosting unconventional chiral fermions that extend beyond the common Dirac and Weyl fermions. B20-type CoSi is a prototypal material that accommodates such an exotic quasiparticle. To date, the spin transport properties in the spin-1 chiral semimetals, have not b...
2106.15107v1
2021-11-13
360° polarization control of terahertz spintronic emitters using uniaxial FeCo/TbCo2/FeCo trilayers
Polarization control of THz light is of paramount interest for the numerous applications offered in this frequency range. Recent developments in THz spintronic emitters allow for a very efficient broadband emission, and especially unique is their ability of THz polarization switching through magnetization control of th...
2111.07118v1
2022-06-07
Non-volatile electric control of spin-orbit torques in an oxide two-dimensional electron gas
Spin-orbit torques (SOTs) have opened a novel way to manipulate the magnetization using in-plane current, with a great potential for the development of fast and low power information technologies. It has been recently shown that two-dimensional electron gases (2DEGs) appearing at oxide interfaces provide a highly effic...
2206.03068v1
2022-08-09
Growth-dependent Interlayer Chiral Exchange and Field-free Switching
Interfacial Dzyaloshinskii-Moriya interaction (DMI) has long been observed in normal metal/ferromagnetic multilayers, enabling the formation of chiral domain walls, skyrmions and other 2D antisymmetric spin textures confined within a single ferromagnetic layer, while more recent works on interlayer DMI reveal new pathw...
2208.04492v1
2022-10-12
Depth-dependent magnetic crossover in a room-temperature skyrmion-hosting multilayer
Skyrmion-hosting multilayer stacks are promising avenues for applications, although little is known about the depth dependence of the magnetism. We address this by reporting the results of circular dichroic resonant elastic x-ray scattering (CD-REXS), micromagnetic simulations, and low-energy muon-spin rotation (LE-$\m...
2210.06070v2
2022-12-15
Emulation of Neuron and Synaptic Functions in Spin-Orbit Torque Domain Wall Devices
Neuromorphic computing (NC) architecture has shown its suitability for energy-efficient computation. Amongst several systems, spin-orbit torque (SOT) based domain wall (DW) devices are one of the most energy-efficient contenders for NC. To realize spin-based NC architecture, the computing elements such as synthetic neu...
2212.07833v1
2023-01-10
Robust mutual synchronization in long spin Hall nano-oscillator chains
Mutual synchronization of N serially connected spintronic nano-oscillators increases their coherence by a factor $N$ and their output power by $N^2$. Increasing the number of mutually synchronized nano-oscillators in chains is hence of great importance for better signal quality and also for emerging applications such a...
2301.03859v1
2023-02-02
Controlling the Skyrmion Density and Size for Quantized Convolutional Neural Networks
Skyrmion devices show energy efficient and high integration data storage and computing capabilities. Herein, we present the results of experimental and micromagnetic investigations of the creation and stability of magnetic skyrmions in the Ta/IrMn/CoFeB/MgO thin film system. We investigate the magnetic-field dependence...
2302.01390v1
2023-04-16
Anomalous and Topological Hall Resistivity in Ta/CoFeB/MgO Magnetic Systems for Neuromorphic Computing Applications
Topologically protected spin textures, such as magnetic skyrmions, have the potential for dense data storage as well as energy-efficient computing due to their small size and a low driving current. The evaluation of the writing and reading of the skyrmion's magnetic and electrical characteristics is a key step toward t...
2304.07742v1
2023-06-28
Suppression of the spin waves nonreciprocity due to interfacial Dzyaloshinskii Moriya interaction by lateral confinement in magnetic nanostructures
Despite the huge recent interest towards chiral magnetism related to the interfacial Dzyaloshinskii Moriya interaction (iDMI) in layered systems, there is a lack of experimental data on the effect of iDMI on the spin waves eigenmodes of laterally confined nanostructures. Here we exploit Brillouin Light Scattering (BLS)...
2306.16310v1
2023-09-27
Impact of surface anisotropy on the spin-wave dynamics in thin ferromagnetic film
The spin-wave dynamics in the thin CoFeB film in Damon-Eshbach geometry are studied in three cases of boundary conditions -- free boundary conditions, symmetrical surface anisotropy, and one-sided surface anisotropy. The analytical model created by Wolfram and De Wames was extended to include perpendicular surface anis...
2309.15583v1
2023-11-15
Low voltage local strain enhanced switching of magnetic tunnel junctions
Strain-controlled modulation of the magnetic switching behavior in magnetic tunnel junctions (MTJs) could provide the energy efficiency needed to accelerate the use of MTJs in memory, logic, and neuromorphic computing, as well as an additional way to tune MTJ properties for these applications. State-of-the-art CoFeB-Mg...
2311.08984v2
2023-11-24
Even-in-magnetic-field part of transverse resistivity as a probe of magnetic order
The detection of a voltage transverse to both an applied current and a magnetic field is one of the most common characterization techniques in solid-state physics. The corresponding component of the resistivity tensor $\rho_{ij}$ can be separated into odd and even parts with respect to the applied magnetic field. The f...
2311.14498v1
2024-03-25
Skyrmionic device for three dimensional magnetic field sensing enabled by spin-orbit torques
Magnetic skyrmions are topologically protected local magnetic solitons that are promising for storage, logic or general computing applications. In this work, we demonstrate that we can use a skyrmion device based on [W/CoFeB/MgO] 1 0 multilayers for three-dimensional magnetic field sensing enabled by spin-orbit torques...
2403.16725v1
2020-09-14
Large field-like torque in amorphous Ru2Sn3 originated from the intrinsic spin Hall effect
We investigated temperature dependent current driven spin-orbit torques in magnetron sputtered Ru2Sn3 (4 and 10 nm) /Co20Fe60B20 (5 nm) layered structures with in-plane magnetic anisotropy. The room temperature damping-like and field-like spin torque efficiencies of the amorphous Ru2Sn3 films were measured to be 0.14 +...
2009.06711v2
2021-11-09
Spintronic emitters for super-resolution in THz-spectral imaging
THz-spectroscopy is an attractive imaging tool for scientific research, especially in life science, offering non-destructive interaction with matter due to its low photon energies. However, wavelengths above $100{\mu}m$ principally limit its spatial resolution in the far-field by diffraction to this regime, making it n...
2111.05023v1
2010-03-24
Dynamical shift condition for unequal mass black hole binaries
Certain numerical frameworks used for the evolution of binary black holes make use of a gamma driver, which includes a damping factor. Such simulations typically use a constant value for damping. However, it has been found that very specific values of the damping factor are needed for the calculation of unequal mass bi...
1003.4681v1
2013-05-21
Characterization and Synthesis of Rayleigh Damped Elastodynamic Networks
We consider damped elastodynamic networks where the damping matrix is assumed to be a non-negative linear combination of the stiffness and mass matrices (also known as Rayleigh or proportional damping). We give here a characterization of the frequency response of such networks. We also answer the synthesis question for...
1305.4961v1
2009-05-20
Eigenvalue asymptotics, inverse problems and a trace formula for the linear damped wave equation
We determine the general form of the asymptotics for Dirichlet eigenvalues of the one-dimensional linear damped wave operator. As a consequence, we obtain that given a spectrum corresponding to a constant damping term this determines the damping term in a unique fashion. We also derive a trace formula for this problem.
0905.3242v1
2002-06-27
Initial-amplitude dependence in weakly damped oscillators
A pedagogically instructive experimental procedure is suggested for distinguishing between different damping terms in a weakly damped oscillator, which highclights the connection between non-linear damping and initial-amplitude dependence. The most common damping terms such as contact friction, air resistance, viscous ...
0206086v1
2007-08-24
Enhancement of the Gilbert damping constant due to spin pumping in noncollinear ferromagnet/nonmagnet/ferromagnet trilayer systems
We analyzed the enhancement of the Gilbert damping constant due to spin pumping in non-collinear ferromagnet / non-magnet / ferromagnet trilayer systems. We show that the Gilbert damping constant depends both on the precession angle of the magnetization of the free layer and on the direction of the magntization of the ...
0708.3323v1
2007-03-12
Quantum estimation of a damping constant
We discuss an interferometric approach to the estimation of quantum mechanical damping. We study specific classes of entangled and separable probe states consisting of superpositions of coherent states. Based on the assumption of limited quantum resources we show that entanglement improves the estimation of an unknown ...
0703091v2
2023-09-20
Evaluating Gilbert Damping in Magnetic Insulators from First Principles
Magnetic damping has a significant impact on the performance of various magnetic and spintronic devices, making it a long-standing focus of research. The strength of magnetic damping is usually quantified by the Gilbert damping constant in the Landau-Lifshitz-Gilbert equation. Here we propose a first-principles based a...
2309.11152v1
2020-11-11
Reduction of back switching by large damping ferromagnetic material
Recent studies on magnetization dynamics induced by spin-orbit torque have revealed a weak dependence of the critical current for magnetization switching on the damping constant of a ferromagnetic free layer. This study, however, reveals that the damping constant nevertheless plays a key role in magnetization switching...
2011.05566v1
2007-05-14
Identification of the dominant precession damping mechanism in Fe, Co, and Ni by first-principles calculations
The Landau-Lifshitz equation reliably describes magnetization dynamics using a phenomenological treatment of damping. This paper presents first-principles calculations of the damping parameters for Fe, Co, and Ni that quantitatively agree with existing ferromagnetic resonance measurements. This agreement establishes th...
0705.1990v1
2015-11-16
Determination of intrinsic damping of perpendicularly magnetized ultrathin films from time resolved precessional magnetization measurements
Magnetization dynamics are strongly influenced by damping. An effective damping constant {\alpha}eff is often determined experimentally from the spectral linewidth of the free induction decay of the magnetization after the system is excited to its non-equilibrium state. Such an {\alpha}eff, however, reflects both intri...
1511.04802v1
2006-06-27
Theoretical limit of the minimal magnetization switching field and the optimal field pulse for Stoner particles
The theoretical limit of the minimal magnetization switching field and the optimal field pulse design for uniaxial Stoner particles are investigated. Two results are obtained. One is the existence of a theoretical limit of the smallest magnetic field out of all possible designs. It is shown that the limit is proportion...
0606681v1
2022-02-10
Non-stationary Anderson acceleration with optimized damping
Anderson acceleration (AA) has a long history of use and a strong recent interest due to its potential ability to dramatically improve the linear convergence of the fixed-point iteration. Most authors are simply using and analyzing the stationary version of Anderson acceleration (sAA) with a constant damping factor or ...
2202.05295v1
2012-08-01
Artificial Neural Network Based Prediction of Optimal Pseudo-Damping and Meta-Damping in Oscillatory Fractional Order Dynamical Systems
This paper investigates typical behaviors like damped oscillations in fractional order (FO) dynamical systems. Such response occurs due to the presence of, what is conceived as, pseudo-damping and meta-damping in some special class of FO systems. Here, approximation of such damped oscillation in FO systems with the con...
1208.0318v1
2005-03-24
Fast magnetization switching of Stoner particles: A nonlinear dynamics picture
The magnetization reversal of Stoner particles is investigated from the point of view of nonlinear dynamics within the Landau-Lifshitz-Gilbert formulation. The following results are obtained. 1) We clarify that the so-called Stoner-Wohlfarth (SW) limit becomes exact when damping constant is infinitely large. Under the ...
0503594v1
2021-02-01
Global existence for semilinear wave equations with scaling invariant damping in 3-D
Global existence for small data Cauchy problem of semilinear wave equations with scaling invariant damping in 3-D is established in this work, assuming that the data are radial and the constant in front of the damping belongs to $[1.5, 2)$. The proof is based on a weighted $L^2-L^2$ estimate for inhomogeneous wave equa...
2102.00909v1
1997-07-23
Riccati parameter modes from Newtonian free damping motion by supersymmetry
We determine the class of damped modes \tilde{y} which are related to the common free damping modes y by supersymmetry. They are obtained by employing the factorization of Newton's differential equation of motion for the free damped oscillator by means of the general solution of the corresponding Riccati equation toget...
9707019v4
2014-01-15
Damping of Terahertz Plasmons in Graphene Coupled with Surface Plasmons in Heavily-Doped Substrate
Coupling of plasmons in graphene at terahert (THz) frequencies with surface plasmons in a heavily-doped substrate is studied theoretically. We reveal that a huge scattering rate may completely damp out the plasmons, so that proper choices of material and geometrical parameters are essential to suppress the coupling eff...
1401.3396v1
2018-03-29
Giant resonant nonlinear damping in nanoscale ferromagnets
Magnetic damping is a key metric for emerging technologies based on magnetic nanoparticles, such as spin torque memory and high-resolution biomagnetic imaging. Despite its importance, understanding of magnetic dissipation in nanoscale ferromagnets remains elusive, and the damping is often treated as a phenomenological ...
1803.10925v1
2018-02-15
Damping's effect on the magnetodynamics of spin Hall nano-oscillators
We study the impact of spin wave damping ($\alpha$) on the auto-oscillation properties of nano-constriction based spin Hall nano-oscillators (SHNOs). The SHNOs are based on a 5 nm Pt layer interfaced to a 5 nm Py$_{100-x-y}$Pt$_{x}$Ag$_{y}$ magnetic layer, where the Pt and Ag contents are co-varied to keep the saturati...
1802.05548v1
2003-09-09
Traveling solitons in the damped driven nonlinear Schrödinger equation
The well known effect of the linear damping on the moving nonlinear Schr\"odinger soliton (even when there is a supply of energy via the spatially homogeneous driving) is to quench its momentum to zero. Surprisingly, the zero momentum does not necessarily mean zero velocity. We show that two or more parametrically driv...
0309031v1
2007-08-28
Linear frictional forces cause orbits to neither circularize nor precess
For the undamped Kepler potential the lack of precession has historically been understood in terms of the Runge-Lenz symmetry. For the damped Kepler problem this result may be understood in terms of the generalization of Poisson structure to damped systems suggested recently by Tarasov[1]. In this generalized algebraic...
0708.3827v3
2008-12-11
Frequency-dependent Drude damping in Casimir force calculations
The Casimir force is calculated between Au thin films that are described by a Drude model with a frequency dependent damping function. The model parameters are obtained from available experimental data for Au thin films. Two cases are considered; annealed and nonannealed films that have a different damping function. Co...
0812.2209v1
2009-11-05
Bloch oscillations in lattice potentials with controlled aperiodicity
We numerically investigate the damping of Bloch oscillations in a one-dimensional lattice potential whose translational symmetry is broken in a systematic manner, either by making the potential bichromatic or by introducing scatterers at distinct lattice sites. We find that the damping strongly depends on the ratio of ...
0911.1108v3
2012-05-11
On radiative damping in plasma-based accelerators
Radiative damping in plasma-based electron accelerators is analyzed. The electron dynamics under combined influence of the constant accelerating force and the classical radiation reaction force is studied. It is shown that electron acceleration cannot be limited by radiation reaction. If initially the accelerating forc...
1205.2436v1
2016-05-23
Large time behaivor of global solutions to nonlinear wave equations with frictional and viscoelastic damping terms
In this paper, we study the Cauchy problem for a nonlinear wave equation with frictional and viscoelastic damping terms. As is pointed out by [8], in this combination, the frictional damping term is dominant for the viscoelastic one for the global dynamics of the linear equation. In this note we observe that if the ini...
1605.07232v1
2021-02-28
Stability for an inverse source problem of the damped biharmonic plate equation
This paper is concerned with the stability of the inverse source problem for the damped biharmonic plate equation in three dimensions. The stability estimate consists of the Lipschitz type data discrepancy and the high frequency tail of the source function, where the latter decreases as the upper bound of the frequency...
2103.00461v1