Crystallographic orientation-dependent piezoelectric response in BaTiO3 thin films and the domain evolution under different temperatures

Abstract

The effects of crystallographic orientation on the domain structures and piezoelectric response of BaTiO3 (BTO) thin films were investigated by piezoresponse force microscopy (PFM) systematically. It is found that the domain structures of BTO films are obviously orientation dependent, and the (111) oriented BTO film shows the best piezoelectric properties. Therefore, the nanoscale polydomain switchings within valid single grains of the BTO(111) thin film were observed by PFM under different temperatures. According to the switching process, the a1/a2c, r/a2c, and a1c/r polydomain states were specially introduced into the theoretical model to describe the temperature-induced polydomain switchings of the BTO(111) thin film. The misfit strain-temperature phase diagram was simulated to present the a1/a2c-r/a2c-a1c/r-p domain switching, which corresponds with the threshold temperature of domain switchings obtained from the experimental results of the BTO(111) thin film.