ACOUSTIC SURFACE WAVES ON METALLIZED AND UNMETALLIZED Bi12GeO20

Abstract

New values for the elastic and piezoelectric constants of Bi12GeO20 and for their temperature derivatives are reported. With these new constants, the predicted value of Δv/v for acoustic surface waves is significantly increased. This prediction has been verified by measurements of the acoustic surface-wave velocity on the metallized and unmetallized (001) surface of Bi12GeO20 and by comparing the observed values with theory. On the (001) plane, the maximum Δv/v occurs in the 〈110〉 direction. The predicted Δv/v is 66×10−4 and the experimentally observed value is (77±15)×10−4.