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We examine a skyrmionium driven over a periodic anisotropy pattern, which consists of disorder free regions and disordered regions. For small defect densities, the skyrmionium flows for an extended range of currents, and there is a critical current above which it transforms into a skyrmion. For increased amounts of quenched disorder, the current needed for the skyrmionium to transform into a skyrmion decreases, and there is a critical disorder density above which a moving skyrmionium is not stable. In the moving state, the skyrmionium to skyrmion transformation leads to a drop in the velocity and the onset of a finite skyrmion Hall angle. We also find a reentrance effect in which the pinned skyrmionium transforms into a skyrmion just above depinning, restabilizes into skyrmionium at larger drives, and becomes unstable again at large currents. We also show that adding a transverse shaking drive can increase the lifetime of a moving skyrmionium by reducing the effect of the pinning in the direction of the drive.
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http://dx.doi.org/10.1088/1361-648X/adc648 | DOI Listing |
Nanoscale
August 2025
Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China.
A magnetic skyrmionium, a composite spin texture formed by merging two topologically distinct skyrmions, is a promising information carrier for high-speed and high-density spintronic devices. Although spin current is a common driving force for skyrmionium dynamics, it can induce Joule heating and compromise device stability. To address this limitation, we investigated a voltage-driven approach for propelling skyrmioniums using discrete electrodes.
View Article and Find Full Text PDFAdv Mater
July 2025
Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489, Berlin, Germany.
Topologically non-trivial magnetic solitons are complex spin textures with a distinct single-particle nature. Although magnetic skyrmions, especially those with unity topological charge, have attracted substantial interest due to their potential applications, more complex topological textures remain largely theoretical. In this work, the stabilization of isolated higher-order skyrmion bags beyond the prototypical π-skyrmion in ferromagnetic thin films is experimentally demonstrate, which has posed considerable challenges to date.
View Article and Find Full Text PDFNano Lett
June 2025
Centro Brasileiro de Pesquisas Físicas (CBPF), Rua Dr Xavier Sigaud 150, Urca, 22290-180, Rio de Janeiro-RJ, Brazil.
Stabilizing magnetic skyrmions is a critical issue in spintronics, impacting data storage and computing. This study investigates skyrmion and skyrmionium phenomena within a hexagonal array of curved nanomagnets. Utilizing atomistic calculations, micromagnetic simulations, and experimental methods such as magnetic force microscopy and electron holography, we analyze the interplay between magnetic parameters, curvature, and the interfacial Dzyaloshinskii-Moriya interaction (iDMI) in the formation of these structures.
View Article and Find Full Text PDFJ Phys Condens Matter
April 2025
Department of Physics, São Paulo State University (UNESP), School of Sciences, Bauru 17033-360, SP, Brazil.
We examine a skyrmionium driven over a periodic anisotropy pattern, which consists of disorder free regions and disordered regions. For small defect densities, the skyrmionium flows for an extended range of currents, and there is a critical current above which it transforms into a skyrmion. For increased amounts of quenched disorder, the current needed for the skyrmionium to transform into a skyrmion decreases, and there is a critical disorder density above which a moving skyrmionium is not stable.
View Article and Find Full Text PDFJ Phys Condens Matter
March 2025
Department of Physics, São Paulo State University (UNESP) School of Sciences, Bauru 17033-360, SP, Brazil.
We compare the driven dynamics of skyrmions, antiskyrmions, and skyrmionium interacting with random disorder, circular defects, and asymmetric potentials. When interacting with a line defect at a constant drive, skyrmions and antiskyrmions show an acceleration effect for motion along the wall and a drop in velocity when they can cross the barrier. In contrast, skyrmionium travels at a reduced velocity when moving along a wall, and exhibits an increase in velocity once it can cross the barrier.
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