Inducing a Tunable Skyrmion-Antiskyrmion System through Ion Beam Modification of FeGe Films

Kavli Affiliate: David Muller

| First 5 Authors: M. B. Venuti, Xiyue S. Zhang, Eric J Lang, Sadhvikas J. Addamane, Hanjong Paik

| Summary:

Skyrmions and antiskyrmions are nanoscale swirling textures of magnetic
moments formed by chiral interactions between atomic spins in magnetic
non-centrosymmetric materials and multilayer films with broken inversion
symmetry. These quasiparticles are of interest for use as information carriers
in next-generation, low-energy spintronic applications. To develop
skyrmion-based memory and logic, we must understand skyrmion-defect
interactions with two main goals — determining how skyrmions navigate
intrinsic material defects and determining how to engineer disorder for optimal
device operation. Here, we introduce a tunable means of creating a
skyrmion-antiskyrmion system by engineering the disorder landscape in FeGe
using ion irradiation. Specifically, we irradiate epitaxial B20-phase FeGe
films with 2.8 MeV Au$^{4+}$ ions at varying fluences, inducing amorphous
regions within the crystalline matrix. Using low-temperature electrical
transport and magnetization measurements, we observe a strong topological Hall
effect with a double-peak feature that serves as a signature of skyrmions and
antiskyrmions. These results are a step towards the development of information
storage devices that use skyrmions and anitskyrmions as storage bits and our
system may serve as a testbed for theoretically predicted phenomena in
skyrmion-antiskyrmion crystals.

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