Nonlinear spin waves in cylindrical ferromagnetic nanowires

We study the nonlinear evolution of bulk spin waves in a charge-free, isotropic ferromagnetic nanowire with negligible surface anisotropy, restricted to the modes with no azimuthal dependence. Using a multiple scale analysis, we find that the magnetization oscillations are always restricted to one particular plane for the Fourier component p=1, while the Fourier component p=2 comes out of the plane. Moreover, the magnetization excitations are governed by the cubic nonlinear Schrödinger equation. We also find that the ferromagnetic nanowire facilitates the propagation of dark solitons with the stable continuous wave