Inhomogeneous ferromagnetism mimics signatures of the topological Hall effect in SrRuO${}_3$ films

Abstract

Topological transport phenomena in magnetic materials are a major topic of current condensed matter research. One of the most widely studied phenomena is the ``topological Hall effect'' (THE), which is generated via spin-orbit interactions between conduction electrons and topological spin textures such as skyrmions. We report a comprehensive set of Hall effect and magnetization measurements on epitaxial films of the prototypical ferromagnetic metal SrRuO${}_3$ the magnetic and transport properties of which were systematically modulated by varying the concentration of Ru vacancies. We observe Hall effect anomalies that closely resemble signatures of the THE, but a quantitative analysis demonstrates that they result from inhomogeneities in the ferromagnetic magnetization caused by a non-random distribution of Ru vacancies. As such inhomogeneities are difficult to avoid and are rarely characterized independently, our results call into question the identification of topological spin textures in numerous prior transport studies of quantum materials, heterostructures, and devices. Firm conclusions regarding the presence of such textures must meet stringent conditions such as probes that couple directly to the non-collinear magnetization on the atomic scale.

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• The 2020 Skyrmionics Roadmap
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• Two-channel anomalous Hall effect in SrRuO3
• Robust skyrmion-bubble textures in SrRuO${}_3$ thin films stabilized by magnetic anisotropy
• Hump-like structure in Hall signal from SrRuO${}_3$ ultra-thin films without inhomogeneous anomalous Hall effect
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Cited by in corpus (10)

• Thickness-dependent quantum transport of Weyl fermions in ultra-high-quality SrRuO3 films
• Advances in Complex Oxide Quantum Materials Through New Approaches to Molecular Beam Epitaxy
• Magnetic skyrmion crystal at a topological insulator surface
• Domain wall skew scattering in ferromagnetic Weyl metals
• Resonant optical topological Hall conductivity from skyrmions
• Separated transport relaxation scales and interband scattering in SrRuO${}_3$, CaRuO${}_3$, and Sr${}_2$RuO${}_4$ thin films
• Angular dependence of Hall effect and magnetoresistance in SrRuO${}_3$-SrIrO${}_3$ heterostructures
• Intra-unitcell cluster-cluster magnetic compensation and large exchange bias in cubic alloys
• Spin-reorientation driven topological Hall effect in Fe4GeTe2
• Bounds and anomalies of inhomogeneous anomalous Hall effects