| This paper describes an investigation of determining acoustical physical constants of ZnO. We obtained three specimens of (001)-, (100)-, and (101)-ZnO crystal substrates prepared from three very small single crystals, grown by the hydrothermal synthesis method. We measured bulk-wave velocities in the frequency range from 50 MHz to 300 MHz and LSAW velocities at 225 MHz using the ultrasonic microspectroscopy (UMS) technology. We observed that the specimens included partially conductive region inside the crystals. We determined the constants more accurately except for e15 and e31. |