AVALANCHE DYNAMICS IN DISORDERED SYSTEMS

Abstract

We describe the complex dynamics of an interface (like a magnetic domain wall) on a disordered landscape. In presence of a small external drive (i.e. an external magnetic filed) the motion of the interface is slow and jerky. Two different regimes can be distinguished: the thermally activated regime where the interface spend most of the time in deep metastable states separated by large barriers (creep regime) and the avalanche regime where motion persists also at zero temperature, but it involves collective re-organizations (depinning). Our results shed light on the interplay between these two regimes and on the avalanche statistics.