Deriving the skyrmion Hall angle from skyrmion lattice dynamics

Brearton, Richard; Turnbull, L. A.; Verezhak, J. A. T.; Hatton, P. D.; Laan, G. van der; Hesjedal, T.

doi:10.1038/s41467-021-22857-y

Cited by 20 publications

(13 citation statements)

References 36 publications

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“…In this geometry, the coexistence between various states is easily observed, since the states are remarkably similar in free energy [23]. This coexistence is easily achieved in real samples and has the potential to be utilised within skyrmionic devices, as these states occupy local minima within the magnetic Hamiltonian, and as such have repulsive interactions [27].…”

Section: H Hmentioning

confidence: 85%

“…In our simulations, an isolated skyrmion is driven downstream towards the two possible exits, guided by edge states [41]. A number of mechanisms have been proposed to induce isolated skyrmion motion, including thermal and magnetic field gradients [27,42,43]. However, despite Cu 2 OSeO 3 being an insulator, we decided to use the only available micromagneticallyimplemented method of using a spin-polarised current (j x = 100 A m −2 ), which drives the skyrmions via spin transfer torque [44].…”

Section: Skyrmionic Transistormentioning

confidence: 95%

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Electric Field Controlled Mechanism for the Deflection of Skyrmions

Moody¹,

Littlehales²,

White³

et al. 2022

Preprint

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Magnetic skyrmions are vortex-like, swirls of magnetisation whose topological protection and particle-like nature have suggested them to be suitable for a number of novel spintronic devices. One such application is skyrmionic computing, which has the advantage over conventional schemes due to the amalgamation of logic calculations and data storage. Using small-angle neutron scattering from Cu2OSeO3, and applying electric and magnetic fields, we find that the direction of the skyrmion-coexisting conical states can be manipulated by varying the electric field, and explain this using a free energy approach.

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Section: H Hmentioning

confidence: 85%

Section: Skyrmionic Transistormentioning

confidence: 95%

Electric Field Controlled Mechanism for the Deflection of Skyrmions

Moody¹,

Littlehales²,

White³

et al. 2022

Preprint

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show abstract

“…16,17 Under the driving current, the spin topology of skyrmion results in a deflection in its trajectory due to the Magnus force 18,19 that is characterized by the skyrmion Hall angle (ϕ SkH ). 17,20 It provides a new degree of freedom to control the skyrmion motion. The skyrmions can be driven by an electric current either via the spin-transfer torque (STT) 21,22 or the spin orbit torque (SOT).…”

Section: ■ Introductionmentioning

confidence: 99%

Reconfigurable Logic Operations via Gate Controlled Skyrmion Motion in a Nanomagnetic Device

Paikaray

Kuchibhotla

Haldar

et al. 2022

ACS Appl. Electron. Mater.

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Owing to the topological protection and the ease of efficient manipulation, skyrmions have emerged as potential candidates for carrying information in future memory and logic devices. Here, we have proposed a reconfigurable skyrmion based two-input logic device architecture. Using micromagnetic simulations, we have demonstrated that the device is capable of performing both OR and AND logic gate functionalities in a reconfigurable manner. Different logic functionality of the device is selected by using a current through a nonmagnetic metallic gate, and the resultant Oersted field controls the trajectory of the skyrmion, which in turn determines the logic states. The logic functions are implemented on a ferromagnet/heavy metal bilayer device structure by virtue of several physical effects, such as the spin−orbit torque, skyrmion−edge repulsion, skyrmion−skyrmion topological repulsion, and skyrmion Hall effect. The skyrmion trajectory has been characterized by estimating the skyrmion Hall angle. A wide range of operations by varying the current density, skyrmion velocity, Dzyaloshinskii−Moriya interaction, magnetic anisotropy, and geometrical parameters have been presented in detail. We believe that our spin orbit torque driven logic design will have potential implications for a high-speed and low-power skyrmion based computing architecture.

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“…For ferromagnetic skyrmions subjected to an applied drive, the skyrmion motion exhibits a skyrmion Hall effect along the skyrmion Hall angle 3, 45,46 θ sk , which arises from the topology of the skyrmions. The intrinsic skyrmion Hall angle θ int sk is proportional to the ratio of the Magnus or gyrotropic term to the dissipative term of the skyrmion dynamics.…”

Section: Introductionmentioning

confidence: 99%

Commensuration Effects on Skyrmion Hall Angle and Drag for Manipulation of Skyrmions on Two-Dimensional Periodic Substrates

Reichhardt,

Reichhardt

2022

Preprint

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We examine the dynamics of an individually driven skyrmion moving through a background lattice of skyrmions coupled to a 2D periodic substrate as we vary the ratio of the number of skyrmions to the number of pinning sites across commensurate and incommensurate conditions. As the skyrmion density increases, the skyrmion Hall angle is nonmonotonic, dropping to low or zero values in commensurate states and rising to an enhanced value in incommensurate states. Under commensuration, the driven skyrmion is channeled by a symmetry direction of the pinning array and exhibits an increased velocity. At fillings for which the skyrmion Hall angle is zero, the velocity has a narrow band noise signature, while for incommensurate fillings, the skyrmion motion is disordered and the velocity noise is broad band. Under commensurate conditions, multi-step depinning transitions appear and the skyrmion Hall angle is zero at low drives but becomes finite at higher drives, while at incommensurate fillings there is only a single depinning transition. As the gyrotropic component of the skyrmion dynamics, called the Magnus force, increases, peaks in the velocity that appear in commensurate regimes cross over to dips, and new types of directional locking effects can arise in which the skyrmion travels along other symmetry directions of the background lattice. At large Magnus forces, and particularly at commensurate fillings, the driven skyrmion can experience a velocity boost in which the skyrmion moves faster than the applied drive due to the alignment of the Magnus-induced velocity with the driving direction. In some cases, an increase of the Magnus force can produce regimes of enhanced pinning when the skyrmion is forced to move along a non-symmetry direction of the periodic pinning array. This is in contrast to systems with random pinning, where increasing the Magnus force generally reduces the pinning effect. We demonstrate these dynamics for both square and triangular substrates, and map out the different regimes as a function of filling fraction, pinning force, and the strength of the Magnus force in a series of dynamic phase diagrams.

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Deriving the skyrmion Hall angle from skyrmion lattice dynamics

Cited by 20 publications

References 36 publications

Electric Field Controlled Mechanism for the Deflection of Skyrmions

Electric Field Controlled Mechanism for the Deflection of Skyrmions

Reconfigurable Logic Operations via Gate Controlled Skyrmion Motion in a Nanomagnetic Device

Commensuration Effects on Skyrmion Hall Angle and Drag for Manipulation of Skyrmions on Two-Dimensional Periodic Substrates

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