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| Open AccessEnergy-efficient superparamagnetic Ising machine and its application to traveling salesman problems
Ising machines are promising for solving NP-hard problems, but current implementations have power consumption and scalability challenges. Si et al. implement an Ising machine consisting of 80 superparamagnetic tunnel junctions with all-to-all connections and apply it to a large-scale travelling salesman problem.
- Jia Si
- , Shuhan Yang
- & Hyunsoo Yang
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Article
| Open AccessCMOS plus stochastic nanomagnets enabling heterogeneous computers for probabilistic inference and learning
Designing energy-efficient and scalable hardware capable of accelerating Monte Carlo algorithms is highly desirable for probabilistic computing. Here, Singh et al. combine stochastic magnetic tunnel junction-based probabilistic bits with versatile field programmable gate arrays to achieve this goa
- Nihal Sanjay Singh
- , Keito Kobayashi
- & Kerem Y. Camsari
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Article
| Open AccessMagnetic droplet soliton pairs
A spin torque nano-oscillator consists of a free magnetic layer and a reference magnetic layer. Many works have examined the behaviour of droplet solitons in the free magnetic layer. Here, Jiang et al. extend this to pair of droplet solitons, with one in the free layer and one in the reference layer.
- S. Jiang
- , S. Chung
- & J. Åkerman
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Article
| Open AccessResonant generation of propagating second-harmonic spin waves in nano-waveguides
Spin waves in magnetic nanosystems offer a potential platform for wave-based signal processing and computing, with a variety of advantages compared to optical approaches. Herein, the authors demonstrate resonant phase matched generation of second harmonic spin waves, enabling the generation of short wavelength spin waves that are otherwise difficult to directly excite.
- K. O. Nikolaev
- , S. R. Lake
- & V. E. Demidov
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Article
| Open AccessTrue amplification of spin waves in magnonic nano-waveguides
True amplification of spin waves by spin-orbit torque, which manifests itself by an exponential increase in amplitude with propagation distance, has so far remained elusive. Here, the authors realize amplification using clocked nanoseconds-long spin-orbit torque pulses in magnonic nano-waveguides.
- H. Merbouche
- , B. Divinskiy
- & V. E. Demidov
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Article
| Open AccessCurrent-induced switching of a van der Waals ferromagnet at room temperature
Fe3GaTe2 is a van der Waals material with a Curie temperature well above room temperature, making it an attractive material for integration into spintronic devices. Here, Kajale et al demonstrate spin-orbit torque induced switching of the magnetization of Fe3GaTe2, above room temperature, using a Pt spin Hall layer.
- Shivam N. Kajale
- , Thanh Nguyen
- & Deblina Sarkar
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Article
| Open AccessInterfacial magnetic spin Hall effect in van der Waals Fe3GeTe2/MoTe2 heterostructure
Charge-to-spin conversion allows for the generation and control of spin polarization via a charge current. Typically, this is done with non-magnetic materials with large spin-orbit interactions such as Platinum. Herein, Dai et al demonstrate an intriguing charge-to-spin mechanism, a magnetic spin Hall effect, in a van der Waals heterostructure.
- Yudi Dai
- , Junlin Xiong
- & Feng Miao
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Article
| Open AccessClocked dynamics in artificial spin ice
Artificial spin ices are nanomagnetic metamaterials, whose collective magnetization self-organizes into extended domains. However, controlling when, where and how domains change has proven difficult, yet is crucial for technological applications. Here, Jensen and Strømberg et al. introduce astroid clocking, which enables controlled, stepwise growth and reversal of magnetic domains, using only global fields.
- Johannes H. Jensen
- , Anders Strømberg
- & Erik Folven
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Article
| Open AccessNon-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points
Exceptional points emerge in systems with loss and gain when loss and gain in the system are balanced. Due to the careful balancing involved, they are highly sensitive to perturbations, making them exceptionally useful for sensors and other devices. Here, Wittrock et al observe a variety of complex dynamics associated with exceptional points in coupled spintronic nano-oscillators.
- Steffen Wittrock
- , Salvatore Perna
- & Vincent Cros
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Article
| Open AccessMagnetoresistive-coupled transistor using the Weyl semimetal NbP
L. Rocchino et al. experimentally demonstrate a magnetic field effect transistor based on the Weyl semimetal NbP as the active channel material. A gate magnetic field is generated by current flowing in an integrated superconductor NbN. The device operation relies on the extreme magnetoresistance of the NbP.
- Lorenzo Rocchino
- , Federico Balduini
- & Cezar B. Zota
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Article
| Open AccessA hard molecular nanomagnet from confined paramagnetic 3d-4f spins inside a fullerene cage
Shortening the inter-spin distance is an effective way to enhance magnetic coupling. However, it is typically challenging to change the inter-ion distance in most magnetic systems. Here, Huang et al present a strategy for enhancing magnetic interactions, by confining a molecular magnetic system inside a carbon fullerene cage, leading to enhanced magnetic properties.
- Chenli Huang
- , Rong Sun
- & Song Gao
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Article
| Open AccessPosition error-free control of magnetic domain-wall devices via spin-orbit torque modulation
For magnetic domain-wall devices, key issue to be addressed is nonstochastic displacement of magnetic domain wall. Here, authors report domain-wall control with a position error-free scheme via spin-orbit torque modulation along nanotrack devices.
- Seong-Hyub Lee
- , Myeonghoe Kim
- & Sug-Bong Choe
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Article
| Open AccessAmphibious epidermal area networks for uninterrupted wireless data and power transfer
Body area networks represent a wearable technology suitable for applications like virtual reality and health monitoring. Here, the study presents a wireless battery-free channel that works reliably in harsh environments, including underwater. It utilizes stretchable magneto-inductive metamaterials to enable uninterrupted communication.
- Amirhossein Hajiaghajani
- , Patrick Rwei
- & Peter Tseng
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Article
| Open AccessElectrically programmable magnetic coupling in an Ising network exploiting solid-state ionic gating
Arranging nanomagnets into a two-dimensional lattice provides access to a rich landscape of magnetic behaviours. Control of the interactions between the nanomagnets after fabrication is a challenge. Here, Yun et al demonstrate all-electrical control of magnetic couplings in a two-dimensional array of nanomagnets using ionic gating.
- Chao Yun
- , Zhongyu Liang
- & Zhaochu Luo
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Article
| Open AccessA magneto-activated nanoscale cytometry platform for molecular profiling of small extracellular vesicles
Exosomal PD-L1 (exoPD-L1) is a biomarker predicting immunotherapeutic responses. Here the authors report NanoEPIC, a nanoscale cytometry platform that enables phenotypic sorting and exoPD-L1 profiling from blood plasma by using magnetic-activated ranking to differentiate exosomal subpopulations.
- Kangfu Chen
- , Bill T. V. Duong
- & Shana O. Kelley
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Article
| Open AccessRevealing intrinsic domains and fluctuations of moiré magnetism by a wide-field quantum microscope
By carefully inducing twists or lattice stacking offsets between two adjacent van der Waals crystals, a superlattice potential can be introduced. This Moire lattice offers an incredibly rich physics, ranging from superconductivity to exotic magnetism, depending on van der Waals materials in question. Here, Du et al. study the magnetic domains in twisted CrI3, and show that despite this domain structure, spin fluctuations are spatially homogenous.
- Mengqi Huang
- , Zeliang Sun
- & Chunhui Rita Du
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Article
| Open AccessDirect determination of high-order transverse ligand field parameters via µSQUID-EPR in a Et4N[160GdPc2] SMM
Single molecule magnets (SMMs) are molecules with magnetic states separated by an energy barrier. These two (or more) states can serve as basis for quantum information processing, but this requires a detailed understanding of the ligand field of the molecule that forms the SMM. Here, Taran et al use a combination of two experimental techniques, µSQUID and EPR, to precisely measure the higher-order ligand field parameters.
- Gheorghe Taran
- , Eufemio Moreno-Pineda
- & Wolfgang Wernsdorfer
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Article
| Open AccessField-free spin-orbit torque switching via out-of-plane spin-polarization induced by an antiferromagnetic insulator/heavy metal interface
Electrically switching perpendicular magnetized ferromagnets using spin-orbit torques without assisting magnetic fields is a major goal for spintronics. Recently, several works have proposed using out-of-plane spin polarized currents to achieve this, but these rely on antiferromagnetic metals with low Neel temperatures. Here, Wang et al show that such out-of-plane spin polarization driven switching can be achieved using the interface of an antiferromagnetic insulator and a heavy metal.
- Mengxi Wang
- , Jun Zhou
- & Yong Jiang
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Article
| Open AccessNon-volatile electric control of spin-orbit torques in an oxide two-dimensional electron gas
A central goal of spintronics is electric control of magnetism. One particularly promising method makes use of spin-orbit torques which arise due to the combination of electric current, and the intrinsic spin-orbit effect in a material. Here, Grezes et al demonstrate non-volatile electrical control of the spin-orbit torque generated at the interface between an oxide and a metal.
- Cécile Grezes
- , Aurélie Kandazoglou
- & Jean-Philippe Attané
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| Open AccessManipulating exchange bias in 2D magnetic heterojunction for high-performance robust memory applications
When an antiferromagnet is in close proximity to a ferromagnet, the antiferromagnet pins the spins of the ferromagnet, resulting in an exchange bias effect. This effect has been instrumental in the development of a variety of spintronic devices. Here, Haung et al. use pressure to tune the exchange bias effect in all van der Waals heterostructure composed of FePSe3/Fe3GeTe2.
- Xinyu Huang
- , Luman Zhang
- & Lei Ye
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Article
| Open AccessNonlinear amplification of microwave signals in spin-torque oscillators
Microwave devices are instrumental in wireless communications. Recently, spintronic-based microwave devices have seen significant interest, with the potential for smaller size, and lower power consumption. Here, Zhu et al demonstrate a spintronic amplifier with record gain, which uses material stacks already employed in industrially fabricated magnetic memories.
- Keqiang Zhu
- , Mario Carpentieri
- & Zhongming Zeng
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Article
| Open AccessReversal of nanomagnets by propagating magnons in ferrimagnetic yttrium iron garnet enabling nonvolatile magnon memory
Spin wave based computing has great promise, offering advantage of low power consumption, aided by the absence of currents and therefore Joule heating. However, the absence of a method of directly storing the information contained in the spin waves represents a significant hurdle. Here, Baumgaertl and Grundler demonstrate the reversal of a nanomagnet via spin waves with small spin wave power requirements.
- Korbinian Baumgaertl
- & Dirk Grundler
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Article
| Open AccessHybrid spin Hall nano-oscillators based on ferromagnetic metal/ferrimagnetic insulator heterostructures
Spin-hall nano-oscillators have potential for use in neuromorphic computing applications. Normally they are based around combination platinum and permalloy. Here, the authors combine a permalloy ferromagnet with a low magnetic damping ferrimagnet, leading to significantly improved performance.
- Haowen Ren
- , Xin Yu Zheng
- & Andrew D. Kent
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Article
| Open AccessLocal bifurcation with spin-transfer torque in superparamagnetic tunnel junctions
There has been much interest in using the probabilistic switching of magnetic tunnel junctions in unconventional computing, but to do so requires a detailed understanding of this switching. Here, Funatsu et al rigorously determine the switching exponents in superparamagnetic tunnel junctions.
- Takuya Funatsu
- , Shun Kanai
- & Hideo Ohno
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Article
| Open AccessElectric-field control of nonlinear THz spintronic emitters
Spintronic terahertz (THz) emitters are a class of magnetic heterostructure where femtosecond laser excitations generate THz radiation emission. While they have great potential, electric field control of spintronic emitter remains a challenge. Here, by combining a spintronic emitter with a piezoelectric substrate, Agarwal et al. demonstrate electric field control of THz emission through induced piezostrain.
- Piyush Agarwal
- , Lisen Huang
- & Ranjan Singh
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Article
| Open AccessDefect-induced monopole injection and manipulation in artificial spin ice
Artificial spin ice systems offer a promising platform to study the motion of emergent magnetic monopoles, but controlled nucleation of monopoles is challenging. Here the authors demonstrate controlled injection and propagation of emergent monopoles in an artificial spin ice utilizing ferromagnetic defects.
- Robert Puttock
- , Ingrid M. Andersen
- & Olga Kazakova
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Article
| Open AccessToggle-like current-induced Bloch point dynamics of 3D skyrmion strings in a room temperature nanowire
In three dimensional systems with broken bulk inversion symmetry, skyrmions can form extended string-like structures. Here, Birch et al use scanning transmission x-ray microscopy to demonstrate the current induced generation and motion of these three dimensional skyrmion strings.
- M. T. Birch
- , D. Cortés-Ortuño
- & G. Schütz
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Article
| Open AccessTailoring electron beams with high-frequency self-assembled magnetic charged particle micro optics
Electron beam manipulation is important for their application in microscopes, lithography instruments, and colliders. Here the authors report a wafer scale, self-assembled, microcoil electrically-driven magnetic charge particle optic device that can be implemented into different configurations for controlling of electron beams.
- R. Huber
- , F. Kern
- & A. Lubk
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Article
| Open AccessFreezing and thawing magnetic droplet solitons
Magnetic droplets are a type of non-topological magnetic soliton, which are stabilised and sustained by spin-transfer torques for instance. Without this, they would collapse. Here Ahlberg et al show that by decreasing the applied magnetic field, droplets can be frozen, forming a static nanobubble
- Martina Ahlberg
- , Sunjae Chung
- & Johan Åkerman
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Article
| Open AccessSuperconducting spintronic tunnel diode
Diodes are characterized by mono-directional flow of current, yet this simplicity belies their critical importance in electronics and optics. Here, Strambini et al demonstrate a superconducting quasi-particle equivalent, achieved by the use of a thin ferromagnetic insulator.
- E. Strambini
- , M. Spies
- & F. Giazotto
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| Open AccessCurrent-induced Néel order switching facilitated by magnetic phase transition
Electrical manipulation of antiferromagnetic order is crucial for future memory devices, but existing switching schemes require a large current density. Here, the authors achieve record low current density switching in FeRh by taking advantage of its antiferromagnetic to ferromagnetic phase transition.
- Hao Wu
- , Hantao Zhang
- & Kang L. Wang
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| Open AccessBinding events through the mutual synchronization of spintronic nano-neurons
Spin-torque nano-oscillators have sparked interest for their potential in neuromorphic computing, however concrete demonstration are limited. Here, Romera et al show how spin-torque nano-oscillators can mutually synchronise and recognize temporal patterns, much like neurons, illustrating their potential for neuromorphic computing.
- Miguel Romera
- , Philippe Talatchian
- & Julie Grollier
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| Open AccessSingle skyrmion true random number generator using local dynamics and interaction between skyrmions
Skyrmions, a kind of topological spin texture, have been considered as having potential for use in spin-based computing. Here, Wang et al. study the local dynamics of skyrmions interacting with pinning sites, demonstrating a skyrmion true random number generator with the magnetic field and spin current as two control parameters.
- Kang Wang
- , Yiou Zhang
- & Gang Xiao
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Article
| Open AccessLight helicity detector based on 2D magnetic semiconductor CrI3
Two-dimensional magnetic semiconductors hold promise for spin- and valleytronic applications. Here, the authors report the realization of light helicity detectors based on graphene/CrI3 van der Waals heterostructures, exhibiting a photocurrent behaviour determined by the magnetic state of CrI3.
- Xing Cheng
- , Zhixuan Cheng
- & Lun Dai
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Article
| Open AccessReadout of an antiferromagnetic spintronics system by strong exchange coupling of Mn2Au and Permalloy
Antiferromagnets offer faster operation speed and immunity to stray fields, however, readout of the Neel vector is difficult. Here, Bommanaboyena et al present a heterostructure of a ferromagnet and antiferromagnet, combining easy readout with the benefits of antiferromagnetic spintronics.
- S. P. Bommanaboyena
- , D. Backes
- & M. Jourdan
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| Open AccessNanoscale neural network using non-linear spin-wave interference
Wave based computing has sparked much interest for neuromorphic computing due to the inherent interconnectedness of such wave based approaches. Here, Papp, Porod and Csaba show how neural networks can be implemented using spin-waves, taking advantage of spin-waves intrinsic non-linearity.
- Ádám Papp
- , Wolfgang Porod
- & Gyorgy Csaba
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Article
| Open AccessElectrically switchable van der Waals magnon valves
A major challenge in magnon based approaches to information processing lies in developing valves to allow or supress the magnon signal. Here, Chen et al demonstrate a van der Waals magnet based magnon valve which can be tuned electrically over an exceptionally wide range.
- Guangyi Chen
- , Shaomian Qi
- & Jian-Hao Chen
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Article
| Open AccessMagnetic memory driven by topological insulators
It remains challenging to integrate topological insulators (TI) with magnetic tunnel junctions (MTJ) for spintronics applications. Here, the authors achieve a large tunneling magnetoresistance ratio and a low switching current density in a TI-MTJ device at room temperature, very promising for TI-driven magnetic memory.
- Hao Wu
- , Aitian Chen
- & Kang L. Wang
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Article
| Open AccessThermally active nanoparticle clusters enslaved by engineered domain wall traps
Assembling nanoparticles on surfaces has great technological potential. Here, Tierno et al demonstrate the confinement of magnetic nanoparticles in traps created by magnetic domain walls. The magnetic gradient and location of the domain walls can be finely tuned, allowing for precise control of the constituent nanoparticles.
- Pietro Tierno
- , Tom H. Johansen
- & Arthur V. Straube
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Article
| Open AccessIonitronic manipulation of current-induced domain wall motion in synthetic antiferromagnets
Synthetic anti-ferromagnets, where two ferromagnetic layers are coupled anti-ferromagnetically via a spacer, are known for their very large current-induced domain wall velocities. Here, Guan et al show that the velocity of the domain walls in synthetic anti-ferromagnetic nanowires can be tuned over a wide range due to reversible oxidization via ionic liquid gating.
- Yicheng Guan
- , Xilin Zhou
- & Stuart S. P. Parkin
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Article
| Open AccessVisualizing the strongly reshaped skyrmion Hall effect in multilayer wire devices
Skyrmions - nanoscale, topological spin textures - are promising elements for next-generation computing due to their efficient coupling to currents in racetrack devices. Here, Tan et al. examine over 20,000 instances of current induced skyrmion motion to unveil a comprehensive picture of skyrmion dynamics across currents and fields.
- Anthony K. C. Tan
- , Pin Ho
- & Anjan Soumyanarayanan
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Article
| Open AccessElectrically connected spin-torque oscillators array for 2.4 GHz WiFi band transmission and energy harvesting
Spin torque oscillators (STOs) are attractive potential alternative for many high frequency applications, due to their small area and CMOS compatibility. Here, Sharma et al succeed in the electrical synchronization of four STOs, and use their setup to demonstrate wireless and battery-free energy harvesting using eight STOs.
- Raghav Sharma
- , Rahul Mishra
- & Hyunsoo Yang
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| Open AccessNanoscale magnonic Fabry-Pérot resonator for low-loss spin-wave manipulation
Compared to electromagnetic waves, the wavelength of spin waves is significantly shorter at gigahertz frequencies, enabling the miniaturisation of wave-based devices. Here, the authors present a magnonic Fabry-Pérot resonator allowing for nanoscale and reconfigurable manipulation of spin waves.
- Huajun Qin
- , Rasmus B. Holländer
- & Sebastiaan van Dijken
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Article
| Open AccessSteering magnonic dynamics and permeability at exceptional points in a parity–time symmetric waveguide
The ability to guide and control magnons is central to their potential in future information processing. Here, using a combination of computations and analytical approaches, the authors propose a magnonic waveguide with a unique gain and loss mechanism.
- Xi-guang Wang
- , Guang-hua Guo
- & Jamal Berakdar
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Article
| Open AccessGiant voltage-controlled modulation of spin Hall nano-oscillator damping
Spin Hall nano-oscillators can be tuned via magnetic fields and the drive current, but individual oscillator control in large arrays remains a challenge. Here, the authors provide individual control of the threshold current and the auto-oscillation frequency by voltage-controlled magnetic anisotropy.
- Himanshu Fulara
- , Mohammad Zahedinejad
- & Johan Åkerman
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Article
| Open AccessRecord thermopower found in an IrMn-based spintronic stack
Antiferromagnetic materials are potentially useful for spintronic applications. Here, the authors report high thermoelectric power value of 390 μV/K Seebeck coefficient in IrMn-based half magnetic tunnel junctions at room temperature.
- Sa Tu
- , Timothy Ziman
- & Haiming Yu
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Comment
| Open AccessPlastic flow and the skyrmion Hall effect
Skyrmions in chiral magnets are a particle-like texture that has been attracting growing interest due to their novel dynamics and possible applications. Here, we discuss the role of disorder and skyrmion-skyrmion interaction in governing their motion under an external drive.
- C. Reichhardt
- & C. J. O. Reichhardt
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Article
| Open AccessPattern generation and symbolic dynamics in a nanocontact vortex oscillator
Controlling chaotic behavior in spintronic devices is promising for signal-processing applications. Here, the authors unveil the symbolic patterns hidden in the magnetization dynamics of a nanocontact vortex oscillator and detail how to control chaos complexity with a single experimental parameter.
- Myoung-Woo Yoo
- , Damien Rontani
- & Joo-Von Kim
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| Open AccessDiameter-independent skyrmion Hall angle observed in chiral magnetic multilayers
Magnetic skyrmions are promising objects for future spintronic devices. However, a better understanding of their dynamics is required. Here, the authors show that in contrast to predictions the skyrmion Hall angle is independent of their diameter and motion is dominated by disorder and skyrmion-skyrmion interactions in the system.
- Katharina Zeissler
- , Simone Finizio
- & Christopher H. Marrows