Elastic Tensor of Sr$_2$RuO$_4$
  The six independent elastic constants of Sr$_2$RuO$_4$ were determined using resonant ultrasound spectroscopy on a high-quality single-crystal specimen. The constants are in excellent agreement with those obtained from pulse-echo experiments performed on a sample cut from the same ingot. A calculation of the Debye temperature using the measured constants agrees well with values obtained from both specific heat and M\"{o}ssbauer measurements. 
Johnpierre Paglione, C. Lupien, W. A. MacFarlane, J. M. Perz, Louis   Taillefer, Z. Q. Mao, Y. Maeno