Current-Induced Spin Wave Instability

Current in conducting ferromagnets imparts angular momentum to the magnetic texture. Above a critical current, an instability is reached wherein this angular momentum transfer is able to overcome intrinsic damping, and spin waves begin to grow exponentially in time. We examine the conditions required to observe this instability for bulk and surface spin waves in different dimensions, and investigate the subsequent spin wave turbulence engendered by nonlinear terms in the Hamiltonian that couple different modes.