Abstract
The room-temperature elastic moduli corresponding to the pure longitudinal and transverse modes in single crystals of the wurtzite phase of ZnO have been determined from ultrasonic wave velocities measurements as a function of pressure up to 10 GPa. All the moduli exhibit a linear dependence on pressure, with positive values for the longitudinal moduli and but negative values for the shear moduli and All modes exhibit anomalous travel time above indicating the onset of a transition to the rocksalt phase. Using recent improvements for ultrasonic measurements in multianvil apparatus, this experimental study on the phase-transformation mechanism is extended to simultaneous high pressures and high temperatures. At high temperatures, decrease and the pressure derivatives of the elastic shear modes become more negative. Thus, the elastic shear softening observed at room temperature is enhanced at elevated temperatures.
- Received 21 November 2000
DOI:https://doi.org/10.1103/PhysRevB.63.224105
©2001 American Physical Society