Berlin 2024 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 29: Poster II

MM 29.25: Poster

Tuesday, March 19, 2024, 17:00–19:00, Poster B

Nanoscopic electromagnetic field measurements in S/TEM — •Laura Niermann, Tore Niermann, Frederik Otto, Hüseyin Çelik, Simon Gäbel, Tolga Wagner, and Michael Lehmann — Technische Universität Berlin, Berlin

The electromagnetic properties of materials are governed by the microscopic electromagnetic fields that reside within them. In semiconductor functionality, examples range from static electric fields emerging due to a doping landscape, over hetero-interfaces between electrically polarized materials, to subtle microscopic responses to external electric or magnetic fields. Within the class of magnetic materials, the dynamic movement of domain walls is an example of this. (Scanning-) transmission electron microscopy (S/TEM) allows two complementary approaches to measure these nanoscopic fields. Both the deflection of an electron probe caused by the fields (differential phase contrast) or the phase shift of the electron waves caused by the electromagnetic potential (electron holography) can be measured quantitatively on a nanometer scale. Here we present current results of nanoscopic electromagnetic characterization, highlighting recent advances in understanding measurement artifacts caused by thin specimen surfaces, interactions with the electron probe, material contrasts and internal strain fields. In addition, novel approaches extend the measurements of electromagnetic fields to nanosecond timescales. We anticipate that these nanoscopic methods of electromagnetic field measurements have now been developed to such an extent that they can be used as a regular tool in solid state and material physics research.

Keywords: Transmission Electron Microscopy; Electric Fields Measurements; Magnetic Fields Measurements; Electron Holography; Differential Phase Contrast