Ferroelectrically active acoustic wave propagation.

The ferroelectrically active acoustic wave equation including electrostriction effects is derived from nonlinear constitutive equations of stress and electric displacement for ferroelectric materials exhibiting significant electrostrictive strain. Electrically controllable acoustic wave propagation is predicted by solving the equation as a function of various acoustic variables, e.g., wave excitation, polarization, dc bias, etc. As examples, the elastic, piezoelectric, and ferroelectric acoustic waves and the electromechanical coupling factors are computed as a function of wave propagation in the [100]-[010] plane of BaTiO3 under thickness excitation mode.