Capturing of a magnetic skyrmion with a hole

Jan Müller and Achim Rosch
Phys. Rev. B 91, 054410 – Published 17 February 2015

Abstract

Magnetic whirls in chiral magnets, so-called skyrmions, can be manipulated by ultrasmall current densities. Here we study both analytically and numerically the interactions of a single skyrmion in two dimensions with a small hole in the magnetic layer. Results from micromagnetic simulations are in good agreement with effective equations of motion obtained from a generalization of the Thiele approach. Skyrmion-defect interactions are described by an effective potential with both repulsive and attractive components. For small current densities a previously pinned skyrmion stays pinned whereas an unpinned skyrmion moves around the impurities and never gets captured. For higher current densities, jc1<j<jc2, however, single holes are able to capture moving skyrmions. The maximal cross section is proportional to the skyrmion radius and to α, where α is the Gilbert damping. For j>jc2 all skyrmions are depinned. Small changes of the magnetic field strongly change the pinning properties; one can even reach a regime without pinning, jc2=0. We also show that a small density of holes can effectively accelerate the motion of the skyrmion and introduce a Hall effect for the skyrmion.

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  • Received 14 November 2014

DOI:https://doi.org/10.1103/PhysRevB.91.054410

©2015 American Physical Society

Authors & Affiliations

Jan Müller* and Achim Rosch

  • Institut für Theoretische Physik, Universität zu Köln, D-50937 Cologne, Germany

  • *jmueller@thp.uni-koeln.de

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Issue

Vol. 91, Iss. 5 — 1 February 2015

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