Gradient scaling phenomenon in microsize flexoelectric piezoelectric composites

The flexoelectric-type piezoelectric composites offer an alternative avenue for the development of piezoelectric ceramics, and since the flexoelectric response is diminished rather than enhanced in lead containing compositions, one of the merits of such composites is that those of highest sensitivity will be lead-free. The composites are fabricated by using certain nonpiezoelectric components with a texture symmetry which breaks up applied uniform fields, leading to the field gradients in the active flexoelectric components of the composites. Since these induced field gradients increase as the composite dimensions decrease, it is logical to expect that the piezoelectric performance of such composites would be enhanced with their reduced sizes. In this letter, we report the experimental studies that confirm such a gradient scaling phenomenon in two flexoelectric piezoelectric composites. The fabrication and measurement of the composites are discussed.