Ultrasonic Phase Comparison Technique and Its Application in Elastic Properties Research in the Solid

A ultrasonic interferometric techniquephase comparison method is introduced. As applications, the ultrasonic velocities propagating in semiconductor GaAs, composites with Si3N4 whiskers, transition metal oxide CoO and high Tc superconductor AgYBa2Cu3O7- were measured. For the sample CoO and AgYBa2Cu3O7- the dependence of ultrasonic velocities on both pressure and temperature also were measured. Using pulse echo overlap method, it is difficult to perform the above measurement. The phase comparison method makes measuring easy and accurate. It offers a wide measuring frequency range, from several megahertz to tens megahertz. The method can be used to measure ultrasonic velocities in thin samples (1~2 mm) and in the samples that have serious ultrasonic attenuation. It is expected to obtain wide application in elastic properties research in the solid.