Flexure mode flexoelectric piezoelectric composites

We present a flexure mode composite design to generate steep transverse strain gradient to exploit large flexoelectric coefficient μ 1122 of ( Ba , Sr ) TiO 3 (BST) ceramics. Very strong direct piezoelectric effect was observed in composites due to the flexoelectricity. In a single unit composite, sharp low frequency ( < 300 Hz ) mechanical resonance leads to high effective d 33 > 2000 pC / N as the result of enhancement of strain gradient at resonance. Giant nonresonance d 33 well beyond piezoelectric single crystal about 4350 pC/N was measured at a temperature around Curie temperature of BST ceramic in a six unit three layer composite.