Chaotic Dynamics During Slow Relaxation Process in Magnon Systems

Abstract

Experimental evidence of chaotic dynamics during a slow relaxation process with very low frequency magnetization auto-oscillations in magnon systems is presented. A ferromagnetic resonance experiment using a sphere of pure yttrium iron garnet (YIG) at the X-band pumping frequency within the coincidence regime reveals a slow relaxation process with a long tail after a stepwise drop in external pumping power. The relaxation process is found to follow a power-law with time as a transient process involving a transition of local dynamics from a quasi-periodic state to a chaotic state as the collapse of torus.