Elastic properties of single- and multi-domain crystals of LiTaO3

A basic study of the differences in elastic properties between single- and multi-domain crystals of LiTaO3 is conducted by measuring the longitudinal velocities for X-, Y-, and Z-cut specimens and the shear velocities for Z-cut specimens. Two sets of X-, Y-, and Z-cut specimens are prepared: one is for normal (single-domain) specimens and the other is for perfectly depoled (multi-domain) specimens. For the longitudinal wave propagation directions along the Y and Z axes, the velocities for the single-domain specimens, due to piezoelectricity, are 91.5 m/s (1.59%) and 92.7 m/s (1.50%) larger than those for the multi-domain specimens, respectively. On the other hand, for the X-axis longitudinal and Z-axis shear wave propagation directions, piezoelectricity is uncoupled, but the very interesting velocity changes are that the longitudinal and shear velocities for the single-domain specimens are 48.4 m/s (0.87%) and 135.6 m/s (3.79%) smaller than those for the multi-domain specimens, respectively. These differences are introduced by the poling operation for multi-domain LiTaO3 crystals. Four elastic constants of c11, c33, c44, and c14 in the multi-domain state are determined.