Measuring the flexoelectric coefficient of bulk barium titanate from a shock wave experiment

摘要

In this paper, a phenomenon of polarization introduced by shock waves is experimentally studied. Although this phenomenon has been reported previously in the community of physics, this is the first time to link it to flexoelectricity, the coupling between electric polarization and strain gradients in dielectrics. As the shock waves propagate in a dielectric material, electric polarization is thought to be induced by the strain gradient at the shock front. First, we control the first-order hydrogen gas gun to impact and generate shock waves in unpolarized bulk barium titanate (BT) samples. Then, a high-precision oscilloscope is used to measure the voltage generated by the flexoelectric effect. Based on experimental results, strain elastic wave theory, and flexoelectric theory, a longitudinal flexoelectric coefficient of the bulk BT sample is calculated to be μ_(11) = 17.33 × 10~(-6) C/m, which is in accord with the published transverse flexoelectric coefficient. This method effectively suppresses the majority of drawbacks in the quasi-static and low frequency dynamic techniques and provides more reliable results of flexoelectric behaviors.