Because of the significant difference in the piezoelectric moduli between lithium niobate and lithium tantalate, variation of the piezoelectric properties in local regions of the crystal can appear. A correlation between the change in the piezoelectric properties and the composition in a mixed lithium niobate–tantalate crystal was established.

The diffraction response of a single crystal to an electric field is measured by X-ray diffraction at angles close to π. Such schemes allow one to determine with high (∼10⁻⁵–10⁻⁶) accuracy the relative changes in the lattice constant.