Determination of the piezoelectric constants of LGN, LGS, and LGT

The piezoelectric constants of LGN (langanite, La/sub 3/Ga/sub 5.5/Nb/sub 0.5/O/sub 14/), LGS (langasite, La/sub 3/Ga/sub 5/SiO/sub 14/) and LGT (langatate, La/sub 3/Ga/sub 5.5/Ta/sub 0.5/O/sub 14/) have been determined over a temperature range of -55/spl deg/C to +125/spl deg/C from measurements of the equivalent circuit parameters of suitably oriented plano-convex resonators. Apart from the piezoelectric temperature coefficients for LGT, which appear to be the first reported, the new values are compared with values previously reported.