A review of langasite material constants from BAW and SAW data: toward an improved data set

The aim of this paper is to derive an improved set of Langasite (LGS) material constants based on BAW and SAW data in order to get a better agreement between theoretical predictions and experimental measurements for wave velocities and temperature effects. In a previous work it was shown that an "aggregate" set of the measured values of bulk wave velocities can provide a improved set of measurement data for BAW propagation. Recent advances in LGS crystal growth and measurement of material properties obtained independently from the original authors allows us to go further, one unsolved problem with previous data being inconsistencies in the temperature derivatives of material constants of LGS. This paper brings together a large quantity of experimental data obtained independently by the authors. Comparison between experiments and theoretical predictions are recomputed taking into account the more recently published data sets for LGS. In combination with a critical analysis of the literature on LGS crystals, an improvement of a "best fit" data set for velocities is proposed.