New elements for a theory of the Barkhausen effect

We present a microscopical model of the domain wall motion through a disordered medium. Unlike a previous phenomenological model, which explains most of the experimental data, the disorder is supposed to be uncorrelated. The dynamical equation of the motion has a upper critical dimension of 3, so that a mean field description is suitable to describe soft magnetic materials. It is shown that the correlation of the disorder is a consequence of the nature of the magnetic interactions and not an intrinsic property of the materials. The mean field critical exponents well agree with the phenomenological model and with simulated and experimental data.