Flexoelectricity of barium titanate

Flexoelectricity was investigated as a function of temperature in paraelectric and ferroelectric phases of barium titanate ceramic. The flexoelectric coefficient mu(12) was measured dynamically at small level of strain gradients. mu(12) is around 5 mu C/m in orthorhombic phase, rises to about 10 mu C/m at room temperature, and peaks at similar to 50 mu C/m near tetragonal-cubic phase transition point. The coupling effect between mechanical strain gradient and electric polarization is found to be nonlinearly enhanced by-high dielectric permittivity and domain contribution in barium titanate. In inhomogeneously strained ferroelectrics, mechanical gradient, field may impact electric polarization in a way analogous to electric field. (c) 2006 American Institute of Physics.