Temperature Dependence of Surface Acoustic Wave Velocity on α Quartz

Abstract

Measurements of the temperature dependence of surface acoustic wave velocity were performed for propagation on X, Y, AC, AT, and along the x axis of several other rotated Y cuts of quartz over the temperature range −25° to +75°C. A pulsed rf technique was employed. To facilitate the measurement of angular dependence of the temperature coefficient of velocity, surface wave delay lines were constructed in which the waves were excited on the quartz by means of an interdigital electrode structure on a glass substrate which was brought into contact with the quartz. Calculations of the temperature coefficients of velocity and delay time were performed using an iterative computer program based on the work of Coquin and Tiersten. The measurements and calculations are in good agreement in most cases, the largest discrepancy being approximately five percent. It is concluded that the orientation which best combines low-temperature dependence of delay time, high coupling constant, and a minimum of deleterious side effects is 42½° rotated Y-cut quartz with propagation along the x axis.