Domain structure and phase symmetry of multiferroic BiFeO3-PbTiO3 single crystals studied by piezoresponse force microscopy.

Piezoresponse force microscopy (PFM) was used to investigate the domain structure of multiferroic BiFeO3-PbTiO3 single crystals with morphotropic phase boundary (MPB) compositions. The PFM data demonstrate the piezoelectricity and the PFM domain responses under the designed experimental setup reveal the coexistence of a rhombohedral, a tetragonal, and an orthorhombic phases in the MPB crystals, which is consistent with the results of structural refinements based on X-ray diffraction data.