Symmetry-dependent ultrafast manipulation of nanoscale magnetic domains

Abstract

There are conflicting reports that ~100 femtosecond optical pumping causes ultrafast magnetic domain rearrangement. Such rearrangement implies a potential for unprecedented domain wall speeds. Ultrafast distortions in diffraction features via magnetic small angle x-ray scattering have been seen in some studies, while they have been absent in others. Here, the controversy is resolved by measuring a sample with domain-pattern symmetry varying from labyrinths to stripes. Importantly, spatial rearrangement occurs with labyrinths but not with stripes, suggesting novel and unexpected physics yet to be understood.