Ultrafast Lorentz Electron Microscopy Study on Spin-Wave Emissions from Topological Magnetic Textures

Microwave-driven spin waves in magnetic thin films are a potential ideal medium for communication, capable of carrying and transmitting information with extremely low energy consumption. They are also a competitive candidate for neuromorphic computing at the nanoscale. Understanding the role of topological magnetic textures in spin-wave generation, propagation, and interference is crucial, as these magnetic textures are nearly inevitable. In this presentation, we report our investigation into the relationship between spin-wave behavior and magnetic textures using microwave-mediated ultrafast Lorentz transmission electron microscopy, which provides picosecond-nanometer spatiotemporal resolution. We found that spin-wave emission favors certain types of magnetic singularities over others and that spin-wave generation has a strong correlation with domain wall behavior. We also investigated the interaction of spin waves with domain boundaries, successfully visualizing effects such as wave interference, reflection, and refraction. The experimental results are supported by micromagnetic simulations, which provide further insight and explanations for the observed phenomena.