Journal Article

FZJ-2020-02250

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Impurity-dependent gyrotropic motion, deflection and pinning of current-driven ultrasmall skyrmions in PdFe/Ir(111) surface

Fernandes, I. L. (Corresponding author)FZJ* ; Chico, J. ; Lounis, S.FZJ*

2020
IOP Publ. Bristol

This record in other databases:    

Please use a persistent id in citations: http://hdl.handle.net/2128/25514  doi:10.1088/1361- 648X/ab9cf0

Abstract: Resting on multi-scale modelling simulations, we explore dynamical aspects characterizing magnetic skyrmions driven by spin-transfer-torque towards repulsive and pinning 3d and 4d single atomic defects embedded in a Pd layer deposited on the Fe/Ir(111) surface. The latter is known to host sub-10 nm skyrmions which are of great interest in information technology. The Landau–Lifshitz–Gilbert equation is parametrized with magnetic exchange interactions extracted from the ab-initio all-electron full potential Korringa–Kohn–Rostoker Green function method, where spin–orbit coupling is added self-consistently. Depending on the nature of the defect and the magnitude of the applied magnetic field, the skyrmion deforms by either shrinking or increasing in size, experiencing thereby elliptical distortions. After applying a magnetic field of 10 T, ultrasmall skyrmions are driven along a straight line towards the various defects which permits a simple analysis of the impact of the impurities. Independently from the nature of the skyrmion-defect complex interaction, being repulsive or pinning, a gyrotropic motion is observed. A repulsive force leads to a skyrmion trajectory similar to the one induced by an attractive one. We unveil that the circular motion is clockwise around pinning impurities but counter clockwise around the repulsive ones, which can be used to identify the interaction nature of the defects by observing the skyrmions trajectories. Moreover, and as expected, the skyrmion always escapes the repulsive defects in contrast to the pinning defects, which require a minimal depinning current to observe impurity avoidance. This unveils the richness of the motion regimes of skyrmions. We discuss the results of the simulations in terms of the Thiele equation, which provides a reasonable qualitative description of the observed phenomena. Finally, we show an example of a double track made of pinning impurities, where the engineering of their mutual distance allows to control the skyrmion motion with enhanced velocity.

---

Contributing Institute(s):

1. Quanten-Theorie der Materialien (IAS-1)
2. Quanten-Theorie der Materialien (PGI-1)
3. JARA-FIT (JARA-FIT)
4. JARA - HPC (JARA-HPC)

Research Program(s):

1. 142 - Controlling Spin-Based Phenomena (POF3-142) (POF3-142)
2. First-principles investigation of single magnetic nano-skyrmions (jias17_20190501) (jias17_20190501)

Appears in the scientific report 2020

---

Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; National-Konsortium ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

---