Domain wall motion by spin-polarized current: a micromagnetic study

TLDR

The study investigates how a spin‑polarized current affects domain‑wall motion in a thin Permalloy strip, concluding that more elaborate spin‑transfer models are required. The authors implement spin‑polarized current via local momentum transfer assuming local equilibrium polarization in the micromagnetic simulation, supported by a one‑dimensional wall‑dynamics model. The simulations predict that the current influences wall velocity and mobility under applied field, but matching experiments would require currents over ten times larger than those used in the simplest model.

Abstract

The effect of a spin-polarized current crossing a domain wall in a thin and narrow Permalloy™ strip is studied by micromagnetic simulations, supported by a one-dimensional model of wall dynamics. We use the simplest way to incorporate the spin-polarized current effect in the micromagnetic formalism; namely, a local momentum transfer under the assumption that the current polarization is in local equilibrium. We predict current influence on wall velocity and mobility under field. However, in order to reach agreement with recent experiments, more than ten times larger currents would be required within this simplest model. Thus, more elaborate models of spin transfer are needed.