The role of stationarity in magnetic crackling noise

Part of Topical articles on Experiments in Complex and Magnetic Materials We discuss the effect of stationarity on the avalanche statistics of Barkhausen noise signals. We perform experimental measurements on an Fe85B15 amorphous ribbon and compare the avalanche distributions measured around the coercive field, where the signal is stationary, with those sampled through the entire hysteresis loop. In the first case, we recover scaling exponents (? ~ 1.38, ? ~ 1.65) close to the commonly observed values for other amorphous materials, while in the second the exponents are significantly larger (? ~ 1.7, ? ~ 2.2). We provide a quantitative explanation of the experimental results through a model for the depinning of a ferromagnetic domain wall. The present analysis sheds light on the unusually high values for the Barkhausen noise exponents measured by Spasojevic' et al (1996 Phys. Rev. E 54 2531).