Regensburg 2022 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 23: Skyrmions 2 (joint session MA/KFM)

KFM 23.9: Talk

Thursday, September 8, 2022, 11:30–11:45, H37

Zero-field skyrmionic states and in-field edge-skyrmions induced by boundary tuning — •Jonas Spethmann, Elena Y. Vedmedenko, Roland Wiesendanger, André Kubetzka, and Kirsten von Bergmann — Universität Hamburg, Hamburg, Germany

When magnetic skyrmions are moved via currents, they do not strictly travel along the path of the current, instead their motion also gains a transverse component. This so-called skyrmion Hall effect can be detrimental in potential skyrmion devices because it drives skyrmions towards the edge of their hosting material where they face potential annihilation. To mitigate this problem it was proposed to create a potential well within the skyrmion hosting material and thereby guide the skyrmions along a desired pathway[1]. Here we have experimentally modified a skyrmion model system–an atomic Pd/Fe bilayer on Ir(111)[2]–by growing a self-assembled ferromagnetic Co/Fe bilayer adjacent to it. Employing spin-polarized scanning tunneling microscopy, we demonstrate that this ferromagnetic rim has an immediate effect on the spin spiral ground state of the Pd/Fe bilayer, stabilizes skyrmions and target states in zero field and prevents skyrmion annihilation at the film edge. Furthermore we show that in applied magnetic fields the Co/Fe gives rise to edge-skyrmions pinned to the Pd/Fe island rim. Finally we have performed spin dynamics simulations to investigate the role of different magnetic parameters in causing these edge effects.

[1] I. Purnama et al., Scientific Reports 5, 10620 (2015).

[2] N. Romming et al. Science 341, 636-639 (2013).