Visibility and Apparent Size of Neel-Type Magnetic Skyrmions in Fresnel Defocus Images of Multilayer Films

Denneulin, Thibaud; Caron, Jan; Mueller-Caspary, Knut; Boulle, Olivier; Kovacs, Andras und Dunin-Borkowski, Rafal E. (2021): Visibility and Apparent Size of Neel-Type Magnetic Skyrmions in Fresnel Defocus Images of Multilayer Films. In: Microscopy and Microanalysis, Bd. 27, Nr. 6: S. 1356-1365

Abstract

Multilayers that comprise thin films of heavy metals and ferromagnets have been shown to host Neel-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 Neel-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)x5 multilayer. We also use simulated Fresnel defocus images of Neel-type magnetic skyrmions to understand the influence of defocus on apparent skyrmion size.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 1431-9276
• Sprache: Englisch