Viscosity tensor components of the langatate and langasite

Full sets of components of viscosity tensor for langasite (La
₃
Ga
₅
SiO
₁₄
) and langatate (La
₃
Ga
_5.5
O
₁₄
Ta
_0.5
) were obtained. This study was done using the method of composite acoustic resonator (HBAR) spectroscopy. Using these data it is possible to evaluate the attenuation coefficient for arbitrary directions of the propagation and polarization of acoustic waves in single crystals of langatate and langasite.