Power-law scaling behavior in Barkhausen avalanches of ferromagnetic thin films

Abstract

We report direct domain observations of Barkhausen avalanches at criticality in Co and MnAs thin films investigated by means of a magneto-optical microscope magnetometer, capable of time-resolved domain observation in real time. Through a statistical analysis of the fluctuating size of Barkhausen jump from numerous repetitive experiments for each sample, the distribution of Barkhausen jump size is found to exhibit a power-law scaling behavior with the critical exponent of similar to 1.33 in both systems. This value is consistent with the two-dimensional prediction of a theoretical model proposed by Cizeau et al. [Phys. Rev. Lett. 79 (1997) 4669]. (c) 2006 Elsevier B.V. All rights reserved.