Chirality-induced antisymmetry in magnetic domain wall speed

Fast-moving domain walls separating regions with spin-up or spin-down states are desirable for high-performance spintronic memory and logic devices. The Dzyaloshinskii–Moriya interaction gives rise to an asymmetric distribution of domain wall speeds in chiral magnetic materials, providing a convenient way to determine the strength of the interaction. However, the recent discovery of additional asymmetries has complicated the analysis of measurements. Now, Sug-Bong Choe from Seoul National University and co-workers have experimentally determined the chiral nature of the additional symmetry for the first time. This contribution, which could arise from either a form of energy dissipation called chiral damping or from natural variations in domain wall widths, can alter domain wall speeds by a factor of 100.