Temperature dependence of acoustic property of Ca3Ta(Ga,Al)3Si2O14 single crystals

Abstract

The temperature dependences of the acoustic properties of Ca3Ta(Ga1−xAlx)3Si2O14 [CTGAS(x)] were experimentally studied as a function of the Al substitution content x. Five specimens, i.e., one each of X-, Y-, and Z-, and two rotated Y-cut specimens, were prepared from each crystal ingot of CTGAS(x) (x = 0, 0.25, 0.50, and 0.75) grown by the Czochralski technique. The longitudinal wave and shear wave velocities of CTGAS(x) were measured at three temperatures ranging from 291 to 300 K, then acoustically related physical constants (elastic, piezoelectric, and dielectric constants and coefficient of thermal expansion) were determined at approximately room temperature. The results revealed that the temperature coefficients of all the constants linearly changed with Al content. By one of the calculations using the constants and their temperature coefficients determined in this study, we demonstrated their capability to predict suitable conditions (i.e., cut angle, propagation direction, and chemical composition) for acoustic wave devices although they were determined in a narrow temperature range.