Notable grain-size dependence of converse piezoelectric effect in BaTiO 3 ceramics

Abstract Converse piezoelectric effect is of critical importance to device applications like actuators, but no systematical investigation concerning the influence of microstructure on it has been reported for BaTiO 3 ceramics so far. Piezoelectric and ferroelectric properties were inclusively investigated for a group of BaTiO 3 ceramics that are fabricated through solid-state reaction route and show various average grain sizes in this study. It was found that the piezoelectric properties of these BaTiO 3 ceramics display significant grain-size dependences. The direct piezoelectric coefficient d 33 increases with decreasing the average grain size (GS) from 170 pC/N at 40 μm, reaches a maximum value of 413 pC/N at 1.2 μm, and then decreases with a further reduction of GS. Converse piezoelectric effect was characterized by measurement of unipolar strain versus electric field ( S – E ) curve, and the converse piezoelectric coefficient d 33 *( E ) was quantitatively calculated from the slope of S – E curve at relatively large E . Interestingly, d 33 *( E ) is nearly twice as large as d 33 and shows a quite similar trend of change with GS to d 33 . It increases largely from 350 pm/V to 870 pm/V when reducing the GS value from 40 μm to 1.2 μm, and then decreases to 480 pm/V with the further GS reduction to 0.7 μm. Meanwhile, the remanent polarization P r shows an increase with the decreasing of GS, reaches a maximum at 3.3 μm, and then decreases with the further GS reduction. Domain structure is considered to play an essential role in determining the notable grain-size dependence of converse piezoelectric effect.