Visualization and manipulation of meta-stable polarization variants in multiferroic materials

Here we demonstrate the role of meta-stable polarization variants in out-of-plane polarization switching behavior in epitaxially grownBiFeO3thin films using angle-resolved piezoresponse force microscopy (AR-PFM). The out-of-plane polarization switching mainly occurred at the boundary between meta-stable and stable polarization domains, and was accompanied by a significant change in in-plane domain configuration from complicated structure with 12 polarization variants to simple stripe structure with 4 polarization variants. These results imply that the biased tip rearranges the delicately balanced domain configuration, which is determined by the competition between electrostatic and strain energies, into simple interweaving one that is more thermodynamically stable.