Materials and fabrication techniques for resonant ultrasound spectroscopy at high and low temperatures

Abstract

Measurement of the mechanical resonances of materials of interest to condensed matter science is becoming increasingly common because it reveals important thermodynamic signatures such as phase transitions, as well as providing sound speeds and stiffness information for technology. Often done using Resonant Ultrasound Spectroscopy, the ultimate precision of measurements is determined by the mechanical Q, not unusually 104 or higher, thereby making it possible to determine changes in elastic moduli at the sub pert-per-million level. However, resonances and changes in the acoustic response of the cell that holds transducers and the specimen to be measured can introduce artifacts as temperatures change, clouding otherwise important observations. We describe here solutions to such problems with acoustically “dead” materials capable of operation from below 1 K to 900 K using easily available starting components. We also describe strategies for electrical contacts at temperature above the melting point of lead-tin solder. Some unusual results are presented.