Transmission electron microscopy is one of the most powerful techniques to characterize nanoscale magnetic structures. In light of the importance of fast control schemes of magnetic states, time-resolved microscopy techniques are highly sought after in fundamental and applied research. Here, we implement time-resolved Lorentz imaging in combination with synchronous radio-frequency excitation using an ultrafast transmission electron microscope. As a model system, we examine the current-driven gyration of a vortex core in a 2 μm-sized magnetic nanoisland. We record the trajectory of the vortex core for continuous-wave excitation, achieving a localization precision of ±2nm with few-minute integration times. Furthermore, by tracking the core position after rapidly switching off the current, we find a temporal hardening of the free oscillation frequency and an increasing orbital decay rate attributed to local disorder in the vortex potential.
@article{arxiv.1907.04608,
title = {Few-nm tracking of magnetic vortex orbits and their decay with ultrafast Lorentz microscopy},
author = {Marcel Möller and John Henri Gaida and Sascha Schäfer and Claus Ropers},
journal= {arXiv preprint arXiv:1907.04608},
year = {2020}
}