Orientation dependence of the intrinsic converse longitudinal piezoelectric constant for 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3ferroelectric films with a rhombohedral structure

The general orientation dependence of the intrinsic converse longitudinal piezoelectric constant dnnf in an epitaxial rhombohedral film is calculated by taking into account the effect of substrate clamping. Theoretical predictions are made for dnnf of epitaxial 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 rhombohedral films, which are compared with experimental results on pseudo-cubic (001), (110) and (111) orientations.