Acoustic analogs of elasticity theory ratios for determining anisotropic Poisson ratios of cubic monocrystals

The authors suggests new parameters for determining anisotropie Poisson's ratios a
_<;hkt>;
of cubic crystals representing combinations of squared ratios of longitudinal and transverse elastic waves velocities along crystallographic directions <;100>; and <;110>;. We showed types of parameter and Poisson's ratio changes in the crystals of solid solutions Sm
_1-x
Y
_x
S which undergo isostructural (NaCl-NaCl) electron (semiconductor-metal) phase transition of the 1
^st
type under the critical concentration of x
_c
= 0.15.