Room temperature surface piezoelectricity in SrTiO3 ceramics via piezoresponse force microscopy

摘要

SrTiO3 ceramics are investigated by piezoresponse force microscopy.Piezoelectric contrast is observed on polished surfaces in both vertical andlateral regimes and depends on the grain orientation varying in both sign(polarization direction) and amplitude. The observed contrast is attested tothe surface piezoelectricity due to flexoelectric effect (straingradient-induced polarization) caused by the surface relaxation. The estimatedflexoelectric coefficient is approximately one order of magnitude smaller ascompared to those recently measured in SrTiO3 single crystals. The observedenhancement of piezoresponse signal at the grain boundaries is explained by thedipole moments associated with inhomogeneous distribution of oxygen vacancies.