Intermittent collective dynamics of domain walls in the creep regime

摘要: We study the ultra slow domain wall motion in ferromagnetic thin films driven by a weak magnetic field. Using time resolved magneto-optical Kerr effect microscopy, we access to statistics of intermittent thermally activated jumps between deep metastable states. Our observations are consistent with existence creep avalanches: roughly independent clusters broad size and ignition waiting-time distributions, each one composed large number spatio-temporally correlated elementary events. Moreover, evidence that scale geometry walls is better described depinning rather than equilibrium universal exponents.