Properties ofHe3at Pressures Greater than the Minimum in the Melting Curve

Abstract

Measurements of the specific heat and velocity of sound in ${\mathrm{He}}^3$ as functions of pressure and temperature have been obtained for temperatures from 0.02 to 0.3°K and pressures greater than the minimum in the melting curve. These measurements indicate that only two phases, liquid and $\alpha$ solid, exist in this region of the phase diagram. The melting curve was measured to 0.03°K. The thermodynamic consistency of the data is discussed in terms of a two-phase model. The data are compared with predictions which assume the solid entropy to be $R\ln 2$, and qualitative agreement is obtained. Additional evidence from magnetic measurements is given in support of the two-phase description.