Correlated spin-wave generation and domain-wall oscillation in a topologically textured magnetic film

Spin waves, or magnons, are essential for next-generation energy-efficient spintronics and magnonics. Yet, visualizing spin-wave dynamics at nanoscale and microwave frequencies remains a formidable challenge due to the lack of spin-sensitive, time-resolved microscopy. Here, in this study, we report a breakthrough in imaging dipole-exchange spin waves in a ferromagnetic film owing to the development of laser-free ultrafast Lorentz electron microscopy, which is equipped with a microwave-mediated electron pulser for high spatiotemporal resolution. Using topological spin textures, we captured the emission, propagation, reflection and interference of spin waves from spin anti-vortices under radio-frequency excitations. Remarkably, we show that spin-wave generation is closely tied to the oscillatory motion of specific magnetic domain walls, providing the missing link between wave emission and wall dynamics near magnetic singularities. This work opens new possibilities in magnonics, offering a nanoscopic view of spin dynamics via transmission electron microscopy and enabling controlled excitation via radio-frequency fields for exploring non-equilibrium states in magnetic and multiferroic systems.. Authors: Liu, Chuhang [Brookhaven National Laboratory (BNL), Upton, NY (United States); Stony Brook University, NY (United States)] (ORCID:0000000171624708); Ai, Fangzhou [University of California, San Diego, CA (United States)] (ORCID:0000000186521082); Reisbick, Spencer [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000278824152); Zong, Alfred [Stanford University, CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)] (ORCID:0000000320473801); Pofelski, Alexandre [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000246539197). DOE Contract: SC0012704; SC0013121. Subjects: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY