Random Spin Wave Envelope Solitons in Magnetic Thin Films

This work reports the formation of temporal solitons from incoherent waves with an instantaneous nonlinearity. One excites a large-amplitude incoherent spin wave packet in a magnetic film. If the coherence time T_c of the incoherent spin waves is longer than the nonlinear response time T_n but shorter than the wave packet duration T, one gets randomly appearing and short-lived spin wave solitons. In spite of the incoherent nature of the overall propagating packet, the solitons show coherent phase profiles.