TEMPERATURE-DEPENDENCE OF THE MOLAR VOLUMES OF LIQUID AND SOLID HE-3 AT MELTING PRESSURE NEAR T-N

For temperatures above the solid ordering temperature T-N = 0.934 mK, the molar volumes v(1) and v(s) of liquid and solid He-3 at melting pr essure, P-m are determined primarily by the melting pressure and the c ompressibility. However, in the vicinity of T-N and below, v(s)(T) is influenced greatly by the expansion coefficient, which becomes large a nd negative. Using existing thermodynamic data, we find that v(s)(T) h as a minimum at T-N with a negative slope for T < T-N. A constant-volu me, all-solid sample starting at T = 0 with the pressure just above P- m would begin to melt as T-N is approached, becoming all-solid again s omewhat above T-N.