Effect of Notch Defects on Superfluid-Like Spin Transport

We examine the effects of pinning potentials (notch defects) on superfluid-like spin transport [1] in magnetic nanostrips using a one-dimensional model and micromagnetic simulations. Our results reveal two distinct dynamic regimes. At driving current densities slightly above the threshold required to induce easy-plane precessional dynamics, a train of individual domain walls with the same chirality propagates along the nanostrip toward the notches. The notches act as a local potential minimum, causing pinning of the domain walls. At higher current densities, we find that a dense train of domain walls constitutes a superfluid-like spin flow that is largely unaffected by the presence of the notches. Such immunity to pinning is more evident in synthetic antiferromagnets, where instabilities via vortex formation are suppressed up to high current densities. Our results suggest that superfluid-like spin transport is robust to edge defects, which might arise due to lithographic patterning, and is therefore promising for future device applications.

References:

[1] E. B. Sonin, Adv. Phys. 59, 181 (2010)