The atomic heat of sodium metal was measured from 0.4 to 2°K using the magnetic refrigerator calorimeter. The experimental data is given by $C=1.32T+0.485\mathrm{}{T}^3$ millijoule/mole-°K. No anomaly is observed in this temperature range. The experimental value of the electronic specific heat and the Pauli spin paramagnetism measured by Schumacher and Slichter are used for comparison with the electronic band theory of sodium and with those modifications introduced by electron-electron and lattice-electron interactions.

• Received 9 November 1959

DOI:https://doi.org/10.1103/PhysRev.118.955