Diffusive and Fluid-like Motion of Homochiral Domain Walls in Easy-Plane Magnetic Strips

Propagation of easy-plane magnetic precession can enable more efficient spin transport than conventional spin waves. Such easy-plane spin transport is typically understood in terms of a hydrodynamic model, partially analogous to superfluids. Here, using micromagnetic simulations, we examine easy-plane spin transport in magnetic strips as the motion of a train of domain walls rather than as hydrodynamic flow. We observe that the motion transitions from diffusive to fluid-like as the density of domain walls is increased. This transition is most evident in notched nanostrips, where the the domain walls are pinned by the notch defect in the diffusive regime but propagate essentially unimpeded in the fluid-like regime. Our findings suggest that spin transport via easy-plane precession, robust against defects, is achievable in strips based on realistic metallic ferromagnets and hence amenable to practical device applications.