Atomic Heats of Normal and Superconducting Tin between 1.2° and 4.5°K

Abstract

Atomic heat measurements on tin in the normal and superconducting states revealed that the electronic contribution to the atomic heat in the superconducting state, ${C}_{\mathrm{es}}$, could be represented below about $0.7{T}_{c}$ by the same exponential expression found applicable to vanadium: $\frac{{C}_{\mathrm{es}}}{\ensuremath{\gamma}{T}_{c}}=a{e}^{\ensuremath{-}\frac{b{T}_{c}}{T}}$, with $a=9.17$ and $b=1.50$. The deduced curve of critical field $\mathrm{vs}$ temperature was in good agreement with ${H}_{c}\ensuremath{-}T$ curves reported from magnetic measurements. The critical field extrapolated to the absolute zero, ${H}_{0}$, was 303.4 oersteds and the transition temperature was 3.722\ifmmode^\circ\else\textdegree\fi{}K. Below 2.5\ifmmode^\circ\else\textdegree\fi{}K the normal atomic heat could be represented by the Sommerfeld-Debye expression with $\ensuremath{\gamma}=1.75\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ joule ${\mathrm{mole}}^{\ensuremath{-}1}$ ${\mathrm{deg}}^{\ensuremath{-}2}$ and $\ensuremath{\Theta}=195.0\ifmmode^\circ\else\textdegree\fi{}$K; above 2.5\ifmmode^\circ\else\textdegree\fi{}K deviation from this expression indicated that $\ensuremath{\Theta}$ decreased with increasing temperature.