A review of elastic constant measurements with resonant ultrasound spectroscopy

Abstract

Measurements of elastic constants in new materials are crucial because the elastic constants, being directly related to atomic and electronic configurations, carry important information about the mechanical and electronic properties and phase transitions. A conventional method for measuring elastic constants, the pulse-echo technique, suffers from a number of problems, such as transducer-sample coupling, parallelism of sample faces, the necessity of remounting transducers, etc. Such problems are avoided in resonant ultrasound spectroscopy (RUS), a relatively new method which can determine all elastic constants in a single measurement. Currently a number of research groups, e.g., UCLA, Los Alamos, Colorado State, University of Wisconsin, University of Nevada, NIST, and laboratories in Europe and Asia are using the RUS technique to study a wide variety of systems, and these will be reviewed in this talk. In our own research, the RUS technique has been extended for studies of very small samples (less than 100 μg) and for measuring the elastic constants in thin film (200 nm) samples. Studies include thin films of magnetic materials involving colossal magnetoresistance (candidates for high density digital data storage media) and films of carbon nanotubes, which have unique mechanical properties. [Research supported by ONR.]