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MA: Fachverband Magnetismus

MA 15: INNOMAG e.V. Prizes 2023 (Diplom-/Master and Ph.D. Thesis)

MA 15.5: Vortrag

Dienstag, 28. März 2023, 10:55–11:20, HSZ 401

Imaging vortex pinning and gyration by time-resolved and in-situ Lorentz microscopy — •Marcel Möller — Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany — 4th Physical Institute - University of Göttingen, Göttingen, Germany

Nanoscopic magnetic textures, including vortices, merons and skyrmions promise future applications three-dimensional memory, logic gates or neuromorphic computing. Studying the control of such textures employing electric, magnetic or optical fields, demands instruments with sufficient spatial and temporal resolution. Ultrafast transmission electron microscopy allows for the study of optically-driven dynamics in materials. Yet, its potential to probe current- or field-driven dynamics of magnetic textures has remained unexplored.

In this work, ultrafast Lorentz imaging is developed to map the time-resolved gyration of vortices in a magnetic nanostructure driven by radio-frequency currents. The tracking of the vortex core with a localization precision of ±2 nm and a temporal resolution below 3 ps is demonstrated [1]. Moreover, we find a transient change in the frequency and damping of the core orbit, attributed to structural disorder in the sample. Combining time-resolved Lorentz microscopy with bright-field imaging is used to identify the origin of this disorder, indicating grain boundaries in the polycrystalline film to be a major source of pinning [2].

[1] M. Möller et al., Commun Phys 3, 36 (2020).

[2] M. Möller et al., Phys. Rev. Research 4, 013027 (2022).