Topological Transitions, Pinning and Ratchets for Driven Magnetic Hopfions in Nanostructures

Fuente: arXiv
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Main Authors: Souza, J. C. Bellizotti, Reichhardt, C. J. O., Reichhardt, C., Saxena, A., Vizarim, N. P., Venegas, P. A.
Format: Preprint
Published: 2025
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author Souza, J. C. Bellizotti
Reichhardt, C. J. O.
Reichhardt, C.
Saxena, A.
Vizarim, N. P.
Venegas, P. A.
author_facet Souza, J. C. Bellizotti
Reichhardt, C. J. O.
Reichhardt, C.
Saxena, A.
Vizarim, N. P.
Venegas, P. A.
contents Using atomistic simulations, we examine the dynamics of three-dimensional magnetic hopfions interacting with an array of line defects or posts as a function of defect spacing, defect strength, and current. We find a pinned phase, a sliding phase where a hopfion can move through the posts or hurdles by distorting, and a regime where the hopfion becomes compressed and transforms into a toron that is half the size of the hopfion and moves at a lower velocity. The toron states occur when the defects are strong; however, in the toron regime, it is possible to stabilize sliding hopfions by increasing the applied current. Hopfions move without a Hall angle, while the toron moves with a finite Hall angle. We also show that when a hopfion interacts with an asymmetric array of planar defects, a ratchet effect consisting of a net dc motion can be realized under purely ac driving.
format Preprint
id arxiv_https___arxiv_org_abs_2501_18827
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Topological Transitions, Pinning and Ratchets for Driven Magnetic Hopfions in Nanostructures
Souza, J. C. Bellizotti
Reichhardt, C. J. O.
Reichhardt, C.
Saxena, A.
Vizarim, N. P.
Venegas, P. A.
Mesoscale and Nanoscale Physics
Using atomistic simulations, we examine the dynamics of three-dimensional magnetic hopfions interacting with an array of line defects or posts as a function of defect spacing, defect strength, and current. We find a pinned phase, a sliding phase where a hopfion can move through the posts or hurdles by distorting, and a regime where the hopfion becomes compressed and transforms into a toron that is half the size of the hopfion and moves at a lower velocity. The toron states occur when the defects are strong; however, in the toron regime, it is possible to stabilize sliding hopfions by increasing the applied current. Hopfions move without a Hall angle, while the toron moves with a finite Hall angle. We also show that when a hopfion interacts with an asymmetric array of planar defects, a ratchet effect consisting of a net dc motion can be realized under purely ac driving.
title Topological Transitions, Pinning and Ratchets for Driven Magnetic Hopfions in Nanostructures
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2501.18827