Fluctuations and Pinning for Individually Manipulated Skyrmions

Fuente: arXiv
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Autori principali: Reichhardt, C. J. O., Reichhardt, C.
Natura: Preprint
Pubblicazione: 2021
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author Reichhardt, C. J. O.
Reichhardt, C.
author_facet Reichhardt, C. J. O.
Reichhardt, C.
contents We numerically examine the dynamics of individually dragged skyrmions interacting simultaneously with an array of other skyrmions and quenched disorder. For drives just above depinning, we observe a broad band noise signal with a $1/f$ characteristic, while at higher drives, narrow band or white noise appears. Even in the absence of quenched disorder, the threshold force that must be applied to translate the driven skyrmion is finite due to elastic interactions with other skyrmions. The depinning threshold increases as the strength of the quenched disorder is raised. Above the depinning force, the skyrmion moves faster in the presence of quenched disorder than in a disorder-free system since the pinning sites prevent other skyrmions from being dragged along with the driven skyrmion. For strong pinning, we find a stick-slip motion of the driven skyrmion which produces a telegraph noise signature. The depinning threshold increases monotonically with skyrmion density in the absence of quenched disorder, but when pinning is present, the depinning threshold changes nonmonotonically with skyrmion density and there are reentrant pinned phases due to a competition between pinning induced by the quenched disorder and that produced by the elastic interactions of the skyrmion lattice.
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id arxiv_https___arxiv_org_abs_2108_13541
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Fluctuations and Pinning for Individually Manipulated Skyrmions
Reichhardt, C. J. O.
Reichhardt, C.
Mesoscale and Nanoscale Physics
We numerically examine the dynamics of individually dragged skyrmions interacting simultaneously with an array of other skyrmions and quenched disorder. For drives just above depinning, we observe a broad band noise signal with a $1/f$ characteristic, while at higher drives, narrow band or white noise appears. Even in the absence of quenched disorder, the threshold force that must be applied to translate the driven skyrmion is finite due to elastic interactions with other skyrmions. The depinning threshold increases as the strength of the quenched disorder is raised. Above the depinning force, the skyrmion moves faster in the presence of quenched disorder than in a disorder-free system since the pinning sites prevent other skyrmions from being dragged along with the driven skyrmion. For strong pinning, we find a stick-slip motion of the driven skyrmion which produces a telegraph noise signature. The depinning threshold increases monotonically with skyrmion density in the absence of quenched disorder, but when pinning is present, the depinning threshold changes nonmonotonically with skyrmion density and there are reentrant pinned phases due to a competition between pinning induced by the quenched disorder and that produced by the elastic interactions of the skyrmion lattice.
title Fluctuations and Pinning for Individually Manipulated Skyrmions
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2108.13541