Studies of Barkhausen Pulses in Ferroelectrics

Systems that produce crackling noises such as Barkhausen pulses are statistically similar and can be compared with one another. In this project, the Barkhausen noise of three ferroelectric lead zirconate titanate (PZT) samples were demonstrated to be compatible with avalanche statistics. The peaks of the slew-rate (time derivative of current $dI/dt$) squared, defined as jerks, were statistically analysed and shown to obey power-laws. The critical exponents obtained for three PZT samples (B, F and S) were 1.73, 1.64 and 1.61, respectively, with a standard deviation of 0.04. This power-law behaviour is in excellent agreement with recent theoretical predictions of 1.65 in avalanche theory. If these critical exponents do resemble energy exponents, they were above the energy exponent 1.33 derived from mean-field theory. Based on the power-law distribution of the jerks, we demonstrate that domain switching display self-organised criticality and that Barkhausen jumps measured as electrical noise follows avalanche theory.