Avalanche properties of the 3d-RFIM

The behaviour of the hysteresis loop in the 3d-Gaussian Random-Field Ising Model at T = 0 has been studied by numerical simulations. We have reviewed the relation between the macroscopic behaviour of the system (magnetization hysteresis loops) and the microscopic observations (avalanches). Conclusions are drawn on a scenario for the behaviour of the system in the thermodynamic limit and give, from a microscopic point of view, the reason for the existence of a macroscopic jump (magnetization discontinuity) in the hysteresis loop for disorder values that are lower than the critical amount of disorder. (C) 2003 Elsevier B.V. All rights reserved.