Self-organized criticality and the Barkhausen effect

The Barkhausen effect was studied in an amorphous alloy. The data exhibit all the attributes of self-organized critical behavior enumerated by Bak, Tang, and Weisenfeld: The distribution of lifetimes and areas of discrete Barkhausen pulses follow power-law distributions, which have been modified to account for finite-size effects as suggested by Kadanoff, Nagel, Wu, and Zhou. The directly measured power spectral density has the form of flicker noise, with exponent and form consistent with those to be expected from the measured distribution of pulse areas and lifetimes in the light of the work of Jensen, Christensen, and Fogedby.