Current-induced dynamics of spiral magnet

TL;DR

This paper investigates how charge currents influence the behavior of spiral magnets, revealing phenomena like spiral shift, magnetization change, and wavenumber variation through numerical simulations and theoretical analysis.

Contribution

It provides a detailed numerical and theoretical study of current-induced effects on spiral magnet dynamics, including phenomena like chaotic behavior and annealing.

Findings

Spiral pattern shifts with velocity proportional to current and damping ratio

Uniform magnetization aligns with or against current based on chirality and damping ratio

Wavenumber of the spiral changes under current influence

Abstract

We study the dynamics of the spiral magnet under the charge current by solving the Landau-Lifshitz-Gilbert equation numerically. In the steady state, the current ${\vec j}$ induces (i) the parallel shift of the spiral pattern with velocity $v=(\beta/\alpha)j$ ($\alpha$, $\beta$: the Gilbert damping coefficients), (ii) the uniform magnetization $M$ parallel or anti-parallel to the current depending on the chirality of the spiral and the ratio $\beta / \alpha $, and (iii) the change in the wavenumber $k$ of the spiral. These are analyzed by the continuum effective theory using the scaling argument, and the various nonequilibrium phenomena such as the chaotic behavior and current-induced annealing are also discussed.