Chaos in ac-driven motion of confined magnetic domain wall

We examined ac-driven motion of a confined magnetic domain wall for its time periodicity in order to explore current-induced chaos of domain wall motion. It is known that the motion is a time periodic or nonperiodic, depending on ac amplitude. We showed that the transition from the time periodic to nonperiodic motion occurs with a period doubling cascade with increasing ac amplitude. In the transition, the attractor changes from a periodic to chaotic one through the cascade and further changes into another chaotic one in a crisis at a higher ac amplitude. We also showed that the transition from nonperiodic to periodic motion with increasing ac amplitude originates from the emergence of the periodic attractor with the disappearance of the chaotic attractor.