Elastic Constants of Indium from 1.4° to 300°K

Abstract

The adiabatic elastic constants of indium have been measured in the temperature range 1.4° to 300°K, using the ultrasonic pulse technique. At 1.4°K no difference between the elastic constants in the super-conducting and normal states is observed to within the available accuracy of about 1 part in ${10}^4$. The bearing of this observation on the recent calorimetric data for indium below 1°K is discussed. From the elastic constant data extrapolated to 0°K, the limiting value of the Debye temperature for indium is calculated to be 111.3°K, with an estimated uncertainty of 1%. An extremely large variation with temperature of the shear constant $\frac{(c_{11}-c_{12})}{2}$ is observed.