Specific Heat of Gallium and Zinc in the Normal and Superconducting States

Abstract

By using a ${\mathrm{He}}^3$ cryostat the specific heat of gallium has been measured between 0.35°K and 4.3°K, and that of zinc between 0.42°K and 4.2°K. Measurements on Ga in the normal state indicate that the coefficient of the electronic specific heat, $\gamma$, is 0.601 millijoule/mole ${\left(\mathrm{°}\mathrm{K}\right)}^2$ while the Debye characteristic temperature $\theta$ at 0°K is 317°K. For Zn, $\gamma =0.640\mathrm{}$ millijoule/mole ${\left(\mathrm{°}\mathrm{K}\right)}^2$; $\theta =309\mathrm{}°$K. The electronic specific heat in the superconducting state, $C_{\mathrm{es}}$, for both metals for $T$ well below the transition temperature, $T_c$ can be represented by the expression $C_{\mathrm{es}}=a\gamma T_c{e}^{-\frac{b{T}_{\mathrm{c}}}{T}}$. For Ga, $T_c=1.087\mathrm{}°$K, $a=7.0\mathrm{}$, and $b=1.35\mathrm{}$. The zinc sample measured has a broad transition, $T_c$ taken as 0.852°K. Also for Zn, $a=6.4\mathrm{}$ and $b=1.27\mathrm{}$. The magnetic threshold field curves are calculated from these specific heat results. The critical field at 0°K for Ga is 59.4 gauss and for Zn, 53.4 gauss.