We report that the irreversible magnetization switching process in ferromagnetic nanoparticles is governed by the formation and dynamics of topological point-defects in the form of hedgehog-antihedgehog pairs. After nucleation, these pairs rapidly separate with speeds exceeding domain wall velocities, and they generate an emergent electric field of solenoidal character and substantial magnitude.
@article{arxiv.1711.03511,
title = {Emergent electromagnetism induced by topological defects created during magnetization reversal in nanowires},
author = {M. Charilaou and H. -B. Braun and J. F. Loeffler},
journal= {arXiv preprint arXiv:1711.03511},
year = {2018}
}