Archives of Acoustics, 25, 1, pp. , 2000

Study of the elastic properties of the lithium tantalate crystal by the Brillouin laser light scattering

T. Błachowicz
Institute of Physics, Silesian University of Technology

The preparation of an experiment is described and measured
values of elastic constants of the piezoelectric LiTaO3 crystal, which belongs
to the rhomboedral symmetry system, are given. As the experimental method, the
Brillouin laser light scattering was applied and the constants from the
hypersonic range of frequencies were measured. Appropriate conditions for the
experimental configurations were determined by the use of a formalism based on
the looking for eigenvalues of a so-called "characteristic matrix" which is a
function of direction of the acoustic wave propagation and the elastic constants
of the medium. Not all the measurement results are in full agreement with
calculations based on ultrasonic data. A dispersion in the velocity of the
acoustic waves can be observed for some direction of propagation due to the
elastic constant changes in the hypersonic frequency range.
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