Influence of nonlocal damping on the field-driven domain wall motion

TL;DR

This paper derives and incorporates nonlocal damping effects into domain wall dynamics models, revealing its significant impact on domain wall motion and explaining previous experimental discrepancies.

Contribution

It provides the complete expression of nonlocal damping in noncollinear magnetization and demonstrates its importance in accurately modeling domain wall dynamics.

Findings

Nonlocal damping slows down field-driven domain wall propagation.

It increases the Walker breakdown field.

It explains discrepancies in experimental domain wall mobility measurements.

Abstract

We derive the complete expression of nonlocal damping in noncollinear magnetization due to the nonuniform spin current pumped by precessional magnetization and incorporate it into a generalized Thiele equation to study its effects on the dynamics of the transverse and vortex domain walls (DWs) in ferromagnetic nanowires. We demonstrate that the transverse component of nonlocal damping slows down the field-driven DW propagation and increases the Walker breakdown field whereas it is neglected in many previous works in literature. The experimentally measured DW mobility variation with the damping tuned by doping with heavy rare-earth elements that had discrepancy from micromagnetic simulation are now well understood with the nonlocal damping. Our results suggest that the nonlocal damping should be properly included as a prerequisite for quantitative studies of current-induced torques in noncollinear magnetization.