Localized ac response and stochastic amplification in a labyrinthine magnetic domain structure in a yttrium iron garnet film

Local ac dynamics of the labyrinthine magnetic domain phase in a yttrium iron garnet was studied with scanning Hall microscopy. The harmonic response of the domain walls in the course of the field-driven labyrinth-to-stripe transition is found to be strongly localized at the disclination defects of the labyrinthine structure. The amplitude of the domain wall oscillations in the vicinity of disclination defects is amplified when Gaussian white noise is added to the harmonic drive. Possible microscopic origins of the noise-induced enhancement of the ac response are discussed.