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Title: Nonequilibrium phases and segregation for skyrmions on periodic pinning arrays

Abstract

Using particle-based simulations, we examine the collective dynamics of skyrmions interacting with periodic pinning arrays, focusing on the impact of the Magnus force on the sliding phases. As a function of increasing pinning strength, we find a series of distinct dynamical phases, including an interstitial flow phase, a moving disordered state, a moving crystal, and a segregated cluster state. The transitions between these states produce signatures in the skyrmion lattice structure, the skyrmion Hall angle, the velocity fluctuation distributions, and the velocity-force curves. The moving clustered state is similar to the segregated state recently observed in continuum-based simulations with strong quenched disorder. The segregation arises from the drive dependence of the skyrmion Hall angle, and appears in the strong pinning limit when the skyrmions have nonuniform velocities, causing different portions of the sample to have different effective skyrmion Hall angles. As a result, we map the evolution of the dynamic phases as a function of the system density, the ratio of the Magnus force to the dissipative term, and the ratio of the number of skyrmions to the number of pinning sites.

Authors:
 [1];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1482952
Alternate Identifier(s):
OSTI ID: 1477560
Report Number(s):
LA-UR-18-27075
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:  
89233218CNA000001; AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 98; Journal Issue: 13; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Material Science

Citation Formats

Reichhardt, C., Ray, D., and Reichhardt, C. J. O.. Nonequilibrium phases and segregation for skyrmions on periodic pinning arrays. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.98.134418.
Reichhardt, C., Ray, D., & Reichhardt, C. J. O.. Nonequilibrium phases and segregation for skyrmions on periodic pinning arrays. United States. doi:10.1103/PhysRevB.98.134418.
Reichhardt, C., Ray, D., and Reichhardt, C. J. O.. Thu . "Nonequilibrium phases and segregation for skyrmions on periodic pinning arrays". United States. doi:10.1103/PhysRevB.98.134418.
@article{osti_1482952,
title = {Nonequilibrium phases and segregation for skyrmions on periodic pinning arrays},
author = {Reichhardt, C. and Ray, D. and Reichhardt, C. J. O.},
abstractNote = {Using particle-based simulations, we examine the collective dynamics of skyrmions interacting with periodic pinning arrays, focusing on the impact of the Magnus force on the sliding phases. As a function of increasing pinning strength, we find a series of distinct dynamical phases, including an interstitial flow phase, a moving disordered state, a moving crystal, and a segregated cluster state. The transitions between these states produce signatures in the skyrmion lattice structure, the skyrmion Hall angle, the velocity fluctuation distributions, and the velocity-force curves. The moving clustered state is similar to the segregated state recently observed in continuum-based simulations with strong quenched disorder. The segregation arises from the drive dependence of the skyrmion Hall angle, and appears in the strong pinning limit when the skyrmions have nonuniform velocities, causing different portions of the sample to have different effective skyrmion Hall angles. As a result, we map the evolution of the dynamic phases as a function of the system density, the ratio of the Magnus force to the dissipative term, and the ratio of the number of skyrmions to the number of pinning sites.},
doi = {10.1103/PhysRevB.98.134418},
journal = {Physical Review B},
issn = {2469-9950},
number = 13,
volume = 98,
place = {United States},
year = {2018},
month = {10}
}

Journal Article:
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