Visibility and Apparent Size of Néel-Type Magnetic Skyrmions in Fresnel Defocus Images of Multilayer Films
Source abstract
Abstract
Abstract Multilayers that comprise thin films of heavy metals and ferromagnets have been shown to host Néel-type magnetic skyrmions at room temperature. Fresnel defocus imaging in Lorentz transmission electron microscopy is a widely used technique for recording magnetic information about skyrmions. However, the visibility of Néel-type skyrmions in Fresnel defocus images is typically low, both because only a small component of their magnetic field contributes to the signal and because of the presence of diffraction contrast from the polycrystalline multilayer structure. Here, we take advantage of the out-of-plane hysteresis in such samples to record background-subtracted Fresnel defocus images. We demonstrate an improvement in magnetic signal-to-noise ratio and spatial resolution by a factor of 3 for a (Pt/Co/NiFe)×5 multilayer. We also use simulated Fresnel defocus images of Néel-type magnetic skyrmions to understand the influence of defocus on apparent skyrmion size.
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Research context
OpenAlex topics: Magnetic properties of thin films · Advanced Electron Microscopy Techniques and Applications · Electron and X-Ray Spectroscopy Techniques
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Forschungszentrum Jülich Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, , 52425 Jülich, Germany
Ludwig-Maximilians-Universität München Department of Chemistry, , Butenandtstrasse 5-13, 81377 Munich, Germany
Université Grenoble Alpes, CNRS, CEA, Grenoble INP, Spintec , Grenoble, France
Funding
Deutsche Forschungsgemeinschaft · Initiative and Network 324 Fund of the Helmholtz Association · DARPA TEE program · European Union’s European Union’s Horizon 2020 Research and Innovation Programme
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