ULTRASONIC ATTENUATION IN ZNO

Results are presented for the temperature and frequency dependence of the attenuation of two piezoelectrically active ultrasonic waves in ZnO: (1) compressional waves propagated along the c axis, and (2) shear waves propagated normal to the c axis and polarized along the c axis. Measurements of the phonon phonon attenuation were made over the frequency range 60 MHz to 3.97 GHz and the temperature range 4.2° to 300°K. The frequency dependence at 40°K is of the 1.0 and 0.7 power for the shear and compressional modes, respectively; at 300°K. the frequency dependence is â1.6 for both modes. The temperature dependence ranges from at least T4 at low temperatures to essentially T0; at 300°K for the shear mode; the temperature dependence for compressional waves at frequencies below 2.0 GHz does not appear to reach a T4 dependence for temperatures down to â20°K. © 1969, Acoustical Society of America. All rights reserved.