  We consider 2D random Ising ferromagnetic models, where quenched disorder is
represented either by random local magnetic fields (Random Field Ising Model)
or by a random distribution of interaction couplings (Random Bond Ising Model).
In both cases we first perform zero- and finite-temperature Monte-Carlo
simulations to determine how the critical temperature depends on the disorder
parameter. We then focus on the reversal transition triggered by an external
field, and study the associated Barkhausen noise. Our main result is that the
critical exponents characterizing the power-law associated with the Barkhausen
noise exhibit a temperature dependence in line with existing experimental
observations.
