РОЗРАХУНОК УСІХ П'ЄЗОЕЛЕКТРИЧНИХ І ПРУЖНИХ КОЕФІЦІЄНТІВ КРИСТАЛІВ LiTaO3 НА ОСНОВІ ВИМІРЯНИХ ШВИДКОСТЕЙ АКУСТИЧНИХ ХВИЛЬ.

This paper presents the results of ultrasonic measurements in trigonal LiTaO3 crystals. The samples of direct section with faces perpendicular to the main crystallographic axes and X/45 sections of LiTaO3 crystals were manufactured for experimental studies. The velocities of longitudinal and transverse acoustic waves along the three principal crystallographic axes and two additional axes in theYZ plane in trigonal crystals of point group 3m LiTaO3 crystals were measured using the pulse-echo overlap method. In the piezoelectric crystals, elastic and electrical properties are related and the propagation of an acoustic wave is accompanied by the appearance of electric fields, which must be taken into account in the calculations. The relations for the complete determination of all components of the matrices of elastic stiffness and piezoelectric coefficients based on all necessary acoustic wave velocities measured were derived from the Christoffel equation for the piezoelectric crystals. Using the obtained ratios, all components of the tensors of piezoelectric coefficients, elastic stiffness constants, as well as all elastic compliances of LiTaO3 crystals are calculated. The obtained results are consistent with the literature data and will be used in further measurements and calculation of the spatial anisotropy of induced (electro-, piezo- and acousto-optical) effects on the same crystal samples in order to select the most effective geometry of their possible practical use. [ABSTRACT FROM AUTHOR]