Crackling Noise And The Random Field Ising Model At Finite Temperature

Matthew Delgado, Physics, UIUC

Cracking noise in response to a changing external conditions is found in many nonequilibrium systems with disorder. We simulate Barkhausen noise in disordered ferromagnets at finite temperature as a prototypical example of crackling noise systems. Using the non-equilibrium random field Ising model (RFIM) one finds power law scaling in the noise power spectrum at zero temperature near a critical disorder. At low enough temperatures and finite ramprate of the external driving field, a crossover from the zero temperature scaling behavior to equilibrium noise is seen at high frequencies. In this work we focus on comparing the simulation results to recent experiments on noise in relaxor ferroelectrics.