  Experimental investigations of the scaling behavior of Barkhausen avalanches
in out-of-plane ferromagnetic films yield widely different results for the
values of the critical exponents despite similar labyrinthine domain
structures, suggesting that universality may not hold for this class of
materials. Analyzing a phase field model for magnetic reversal, we show that
avalanche scaling is bounded by characteristic lengthscales arising from the
competition between dipolar forces and exchange interactions. We compare our
results with the experiments and find a good qualitative and quantitative
agreement, reconciling apparent contradictions. Finally, we make some
prediction, amenable to experimental verification, on the dependence of the
avalanches behavior from the film thickness and disorder.
