Local variations of the piezoelectric properties of an LiNb_(1−x)Ta _x O₃ crystal

An in situ study of the spatial distribution of the piezoelectric properties of an LiNb (1− x ) Ta x O 3 crystal (〈 x 〉 = 0.088) in an external DC electric field was performed by the method of X-ray diffraction of synchrotron radiation at angles close to 180°. The variation of the d 22 piezoelectric coefficient was determined with high accuracy (up to 2%) in local areas by the angular shift of the diffraction maximum under the action of the electric field ( E = 1582 V mm −1 ) applied on the crystal along the Y axis, during scanning along the X and Z directions. A correlation between the piezoelectric strain amplitude and the concentration of tantalum obtained by X-ray fluorescence mapping has been established.