Heat Transport in LiquidHe3

The thermal conductivity of liquid ${\mathrm{He}}^3$ at a pressure of $\frac{2}{3}$ atmosphere has been determined experimentally and found to increase slowly from 7×${10}^{-5\mathrm{}}$ watt/cm°K at 0.24°K to 16×${10}^{-5\mathrm{}}$ watt/cm°K at 2.7°K with no evidence of superfluidity. Several models of liquid ${\mathrm{He}}^3$ based on Fermi-Dirac statistics predict a $\frac{1}{T}$ dependence for the thermal conductivity of ${\mathrm{He}}^3$ at the lowest temperatures, but no such behavior has been observed down to 0.24°K in the present work. A study of the convective heat transport in the liquid has indicated that the coefficient of thermal expansion becomes negative below about 0.5°K. A thermal boundary resistance across a copper-liquid ${\mathrm{He}}^3$ interface has been found which is similar in magnitude and temperature dependence to that found for a copper-superfluid ${\mathrm{He}}^4$ boundary.