Theoretical study of current-induced domain wall motion in magnetic nanotubes with azimuthal domains, including {\OE}rsted field and spin-transfer torques

TL;DR

This paper provides a theoretical analysis of current-induced domain wall motion in magnetic nanotubes, considering effects like the Oersted field and curvature-induced anisotropy, and identifies conditions for high-speed domain wall movement.

Contribution

It introduces a combined analytic and simulation approach to understand domain wall dynamics in nanotubes, highlighting effects unique to tubular geometry and determining optimal parameters for fast domain wall motion.

Findings

Identification of Bloch and Néel walls depending on tube geometry and anisotropy

Determination of Walker breakdown current in various regimes

Guidelines for achieving high domain wall speeds

Abstract

We report a theoretical overview of the magnetic domain wall behavior under an electric current in infinitely-long nanotubes with azimuthal magnetization, combining the $1$D analytic model and micromagnetic simulations. We highlight effects that, besides spin-transfer torques already largely understood in flat strips, arise specifically in the tubular geometry: the \OErsted field and curvature-induced magnetic anisotropy resulting both from exchange and material growth. Depending on both the geometry of the tube and the strength of the azimuthal anisotropy, Bloch or N\'eel walls arise at rest, resulting in two regimes of motion largely dominated by either spin-transfer torques or the \OErsted field. We determine the Walker breakdown current in all cases, and highlight the most suitable parameters to achieve high domain wall speed.