Ferroelectric switching in BiFeO3 multiferroic thin films with intrinsic ``stripe-like'' and ``bubble-like'' polydomain configurations was studied by piezoresponse force microscopy. Using the local electric field applied by a scanning probe microscope tip, we observe reversal of both out-of-plane and in-plane components of the polarization, with the final domain state depending on the tip sweeping direction. In ``bubble-like'' samples, complete control of the polarization is achieved, with in-plane polarization change mediated and stabilized by out-of-plane polarization reversal. In ``stripe-like'' samples the intrinsic domain structure influences polarization switching and in-plane reversal may occur without out-of-plane change. The observed switching behaviour can be well correlated with the radial and vertical components of the highly inhomogeneous electric field applied by the tip.
@article{arxiv.0907.4568,
title = {Nanoscale polarization switching mechanisms in multiferroic BiFeO$_3$ thin films},
author = {H. Béa and M. Bibes and A. Barthélémy and P. Paruch},
journal= {arXiv preprint arXiv:0907.4568},
year = {2009}
}