Monopole-Induced Emergent Electric Fields in Ferromagnetic Nanowires.

We predict that complete magnetization reversal in simple metallic ferromagnetic nanoparticles is directly linked to the pair creation of topological point defects in the form of hedgehog-antihedgehog pairs. These dynamical point defects move at exceptionally high speeds in excess of 1500  m/s, faster than any other known magnetic object. Their rapid motion generates unprecedented solenoidal emergent fields on the order of megavolts per meter, in analogy to the magnetic field of a moving electric charge, providing a striking example that a moving hedgehog constitutes an emergent magnetic monopole.