Structural defects and non-ferroelectric piezoelectricity in an unpoled SrTiO3-Bi12TiO20 (ST-BT) composite ceramics

Anomalous piezoelectricity SrTiO3-Bi12TiO20 (ST-BT) composite ceramics fabricated by traditional sintering technology were first studied by positron annihilation lifetime spectroscopy and Doppler broadening spectroscopy. A large number of crystal defects were observed in ST-BT composite ceramics with the sintering temperature below 980 degrees C. The piezoelectric effect appeared concurrently with a high concentration of single-vacancy defects in the ceramics, suggesting that it may be closely related to the microstructure. This further proves that the flexoelectric effect is the origin of non-ferroelectric piezoelectricity. (C) 2012 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.