Using the model system of ferroelectric domain walls, we explore the effects of long-range dipolar interactions and periodic ordering on the behavior of pinned elastic interfaces. In piezoresponse force microscopy studies of the characteristic roughening of intrinsic 71{\deg} stripe domains in BiFeO3 thin films, we find unexpectedly high values of the roughness exponent {\zeta} = 0.74 ± 0.10, significantly different from those obtained for artificially written domain walls in this and other ferroelectric materials. The large value of the exponent suggests that a random field-dominated pinning, combined with stronger disorder and strain effects due to the step-bunching morphology of the samples, could be the dominant source of pinning in the system.
@article{arxiv.1402.3919,
title = {Domain Wall Roughness in Stripe Phase BiFeO$_3$ Thin Films},
author = {B. Ziegler and K. Martens and T. Giamarchi and P. Paruch},
journal= {arXiv preprint arXiv:1402.3919},
year = {2014}
}