Local piezoelectricity in SrTiO3-BiTiO3 ceramics

Local piezoelectric properties of Bi-doped SrTiO3 ceramics have been investigated by piezoresponse force microscopy. The appearance of both out-of-plane and in-plane polarization components confirmed the piezoelectric nature of the obtained signal. The absence of labyrinth-like structures in observed piezoelectric contrast is not consistent with the expected existence of a relaxor ferroelectric state in this material. The close similarity of local piezoelectric properties in Bi-doped SrTiO3 with pure SrTiO3 suggests that the origin of obtained piezoresponse can be attributed to the flexoelectric phenomenon. Bi-doping leads to occurrence of oxygen vacancies and negative charge on the surface of the sample.