Berlinite, a temperature-compensated material for surface acoustic wave applications

Abstract

The surface and pseudosurface acoustic wave properties of berlinite (α-AlPO₄) have been theoretically predicted in order to evaluate the merit of using this material in related surface acoustic wave devices. The surface and pseudosurface acoustic wave velocities, an estimate of the electromagnetic to acoustic coupling, the temperature coefficient of delay, the powerflow angle, and the attenuation have been determined for several standard crystallographic cuts. These results supplement the results given by Carr and O'Connell. This material is shown to possess several temperature-compensated cuts and about four times the coupling of α-quartz. It is pointed out that α-AlPO₄ may be only one of many potentially temperature-compensated materials with a silica derivative-type structure.