Temperature Dependence of the Elastic Surface Wave Velocity on LiNbO₃and LiTaO₃

Calculations of temperature coefficients of the elastic surface wave velocity and delay time were performed for the propagation along the X axis of a rotated Y cut plane of LiNbO 3 and LiTaO 3 . Measurements of the temperature dependence of the delay time of the elastic surface wave were also performed for the propagation along the X axis of a 131° rotated Y cut plane of LiNbO 3 in the temperature range from liquid He to room temperatures. The experimental value, 70×10 -6 /°C, of the temperature coefficient of the delay time from 173 K to room temperature agrees with the calculated value, 72.7×10 -6 /°C. However, the coefficient becomes 16×10 -6 /°C near liquid He temperatures.