Enhanced flexoelectricity through residual ferroelectricity in barium strontium titanate

Residual ferroelectricity is observed in barium strontium titanate ceramics over 30 degrees C above the global phase transition temperature, in the same temperature range in which anomalously large flexoelectric coefficients are reported. The application of a strain gradient leads to strain gradient-induced poling or flexoelectric poling. This was observed by the development of a remanent polarization in flexoelectric measurements, an induced d(33) piezoelectric response even after the strain gradient was removed, and the production of an internal bias of 9 kV m(-1). It is concluded that residual ferroelectric response considerably enhances the observed flexoelectric response. (C) 2015 AIP Publishing LLC.