Improved material constants for LiNbO/sub 3/ and LiTaO/sub 3

Measurements of SAW (surface acoustic wave) velocities on the entire surface of free and metallized substrates of 128 degrees rotY-LiNbO/sub 3/ are reported. The influence of mechanical loading is examined. All experimental data are given as trigonometric expansions. Improved sets of material constants for LiNbO/sub 3/ and LiTaO/sub 3/ are calculated by fitting them to the experimentally determined SAW velocities. In agreement with R. Graham (1977), a significantly larger value of e/sub 33/ was found for LiNbO/sub 3/. While all material constants of LiBnO/sub 3/ and most of LiTaO/sub 3/ have reasonable error bounds, further improvements are expected from more accurately measured unclamped permittivities. >