Experimental studies of the converse flexoelectric effect induced by inhomogeneous electric field in a barium strontium titanate composition

Recent experimental studies have shown that some inhomogeneously strained bulk solid dielectrics have large flexoelectric coefficients. Here we report the experimental observation of the converse flexoelectric effect, i.e., the elastic stress induced in a Ba0.67Sr0.33TiO3 (BST) composition trapezoid block under the inhomogeneous electric fields generated by its chosen boundary shape. This BST composition has a very high electric susceptibility value chi and a ferroelectric Curie point that is close to room temperature. The quantitative measurement of the flexoelectric coefficient mu(11) at a temperature just above the Curie point indicates that an enhanced converse flexoelectric effect exists in the BST sample in good agreement with the earlier measured direct effect. This observed phenomenon agrees with the theoretical predictions of Tagantsev's phenomenological model. Furthermore, our experimental results suggest that we may be able to develop a method to design some unusual but useful piezocomposites with microscale artificial geometry shapes, which are completely fabricated from nonpiezoelectric materials. (c) 2006 American Institute of Physics.