Atomic Heats of Normal and Superconducting Thallium

Abstract

The atomic heats of thallium have been measured in the liquid helium temperature range. In the normal state the atomic heat varies with temperature according to the form: ${C}_{n}=\ensuremath{\gamma}T+464.4{(\frac{T}{\ensuremath{\theta}})}^{3}$ cal/mole deg in which $\ensuremath{\gamma}=6.11\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ cal/mole ${\mathrm{deg}}^{2}$ and $\ensuremath{\theta}=86.6\ifmmode^\circ\else\textdegree\fi{}$. In the superconducting state, at temperatures below $0.9{T}_{c}$, the electronic specific heat obeys the relationship: ${C}_{\mathrm{SE}}=\ensuremath{\gamma}{T}_{c}A\mathrm{exp}(\ensuremath{-}\frac{\ensuremath{\alpha}{T}_{c}}{T})$ cal/mole deg, in which $A=5.8$ and $\ensuremath{\alpha}=1.3$. These results lend support to the suggestion made in consequence of recent measurements of the atomic heats of aluminum, vanadium, and tin that the electronic specific heat may in general be an exponential function of temperature. They do not confirm, however, the suggestion that there exists a law of corresponding states among superconductors.