Pressure Dependence of Elastic Constants and of Superconductivity forV3Ge

Abstract

The pressure dependence of the single-crystal elastic constants of ${\mathrm{V}}_{3}$Ge was measured ultrasonically by the pulse-superposition method as a function of temperature from 10.5 to 298 \ifmmode^\circ\else\textdegree\fi{}K. The pressure derivatives of ${c}_{11}$ and of ${c}_{s}=\frac{({c}_{11}\ensuremath{-}{c}_{12})}{2}$ are strongly temperature dependent. They become negative and show minima at low temperature. The low- and high-temperature limits of the Gr\"uneisen parameters, ${\ensuremath{\gamma}}_{0}$ and ${\ensuremath{\gamma}}_{\ensuremath{\infty}}$ calculated in the anisotropic-elastic-continuum approximation are compatible with the available data for the thermal Gr\"uneisen parameter. The pressure coefficient of the superconducting transition temperature calculated from the elastic data has the proper sign and order of magnitude as, but is smaller than, the experimental value.