Current-induced dynamics of spiral magnet

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.