The noise of the needle: Avalanches of a single progressing needle domain in LaAlO3

The propagation of a single ferroelastic needle domain under weak elastic stress consists of two parts: a continuous front propagation and jerky avalanches. Optical observation and themodynamic analysis show that the continuous behavior is thermally activated. The avalanches follow power law behavior with an energy exponent ε=−1.8±0.2 in agreement with self-similar avalanches close to the depinning threshold. Our experiments on ferroelastic LaAlO3 exclude nucleation of secondary domains, so that the observed behavior is related exclusively to the statistical behavior of one single needle domain.