Large bipolar strain of up to 0.36% (peak-to-peak value) was measured in BiFeO3 ceramics at low frequency (0.1 Hz) and large amplitude (140 kV/cm) of the driving field. This strain is comparable to that achievable in highly efficient Pb-based perovskite ceramics, such as Pb(Zr,Ti)O3 and Pb(Mg,Nb)O3-PbTiO3. The strain showed a strong dependence on the field frequency and is likely largely associated with domain switching involving predominantly non-180{\deg} domain walls. In addition, rearrangement of charged defects by applying electric field of low frequency depins these domain walls, resulting in a more efficient switching and, consequently, an increased response.
@article{arxiv.1104.2440,
title = {Large electric-field induced strain in BiFeO3 ceramics},
author = {Tadej Rojac and Marija Kosec and Dragan Damjanovic},
journal= {arXiv preprint arXiv:1104.2440},
year = {2011}
}