Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 55: Electron theory and micromagnetism

MA 55.11: Vortrag

Freitag, 5. April 2019, 12:15–12:30, H38

Micromagnetic Study of Magnetization States in FeGe Nanospheres — •Swapneel Amit Pathak and Riccardo Hertel — Université de Strasbourg et CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 67000 Strasbourg, France

Magnetic structures in nanoscale ferromagnets are known to depend strongly on the particle size and shape, with recent attention being drawn towards three-dimensional nanomagnets [1]. However, in the case of chiral magnets, with pronounced Dzyaloshinskii-Moriya interaction, three-dimensional finite-size effects remain largely unexplored. Most of the studies on these materials pertain to thin-film geometries or disk shapes [2]. In this work, we employ micromagnetic finite-element simulations to investigate magnetic structures unfolding in FeGe particles of spherical shape. We find a variety of chiral equilibrium states as a function of the diameter and the external applied field. The structures can be categorized as helical states, merons, skyrmions, and chiral bobbers in different variants. The results, summarized in a phase diagram, show that specific magnetic structures can be stabilized depending on the particle size. For example, chiral bobbers can occur at much smaller dimension (r ≥ 50nm) as compared to skyrmions (r ≥ 70nm). The study furthers the understanding of these complex spin structures, which have recently been proposed as candidates for fundamental units of information in spintronics applications [3].

[1] A. Fernandez-Pacheco et al., Nat. Comm., 8, 15756 (2017)

[2] M. Beg em et al., Sci. Rep., 5, 17137 (2015)

[3] F. Zheng et al., Nat. Nano., 13, pp. 451-455 (2018)