Influence of material defects on current-driven vortex domain wall mobility

TL;DR

This paper investigates how material defects influence the mobility of vortex domain walls driven by current in magnetic nanowires, highlighting the significant impact of disorder on experimental measurements of spin-transfer torque.

Contribution

It demonstrates through micromagnetic simulations that distributed disorder significantly affects vortex domain wall mobility, explaining discrepancies in nonadiabaticity measurements.

Findings

Disorder reduces vortex domain wall mobility.

Material defects cause lower measured nonadiabaticity.

Simulations align with experimental observations.

Abstract

Many future concepts for spintronic devices are based on the current-driven motion of magnetic domain walls through nanowires. Consequently a thorough understanding of the domain wall mobility is required. However, the magnitude of the nonadiabatic component of the spin-transfer torque driving the domain wall is still debated today as various experimental methods give rise to a large range of values for the degree of nonadiabaticity. Strikingly, experiments based on vortex domain wall motion in magnetic nanowires consistently result in lower values compared to other methods. Based on the micromagnetic simulations presented in this contribution we can attribute this discrepancy to the influence of distributed disorder which vastly affects the vortex domain wall mobility, but is most often not taken into account in the models adopted to extract the degree of nonadiabaticity.