TY  - JOUR
AU  - Denneulin, Thibaud
AU  - Caron, Jan
AU  - Müller-Caspary, Knut
AU  - Boulle, Olivier
AU  - Kovács, András
AU  - Dunin-Borkowski, Rafal E.
TI  - Visibility and Apparent Size of Néel-Type Magnetic Skyrmions in Fresnel Defocus Images of Multilayer Films
JO  - Microscopy and microanalysis
VL  - 27
IS  - 6
SN  - 1435-8115
CY  - New York, NY
PB  - Cambridge University Press
M1  - FZJ-2021-04059
SP  - 1356-1365
PY  - 2021
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000729816600007
DO  - DOI:10.1017/S1431927621012927
UR  - https://juser.fz-juelich.de/record/902149
ER  -