%0 Journal Article
%A Denneulin, Thibaud
%A Caron, Jan
%A Müller-Caspary, Knut
%A Boulle, Olivier
%A Kovács, András
%A Dunin-Borkowski, Rafal E.
%T Visibility and Apparent Size of Néel-Type Magnetic Skyrmions in Fresnel Defocus Images of Multilayer Films
%J Microscopy and microanalysis
%V 27
%N 6
%@ 1435-8115
%C New York, NY
%I Cambridge University Press
%M FZJ-2021-04059
%P 1356-1365
%D 2021
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000729816600007
%R 10.1017/S1431927621012927
%U https://juser.fz-juelich.de/record/902149