Specific heat below 3 °K of a gold–zinc and a gold–indium alloy

Abstract

Face-centered-cubic alloys of gold with 10 atomic % zinc (divalent) and 10 atomic % indium (trivalent), respectively, were measured in the range 0.4 to 3.0 °K. The coefficients of the nuclear specific-heat term were 1.80 ± 0.07 μcal °K/g atom for AuZn and 1.29 ± 0.06 μcal °K/g atom for AuIn (95% confidence limits). For a gold–10 atomic % silver (monovalent) alloy (Martin 1968) the nuclear term was 0.44 μcal °K/g atom. These results show that electric field gradients in alloys are not simply proportional to the valence difference of the components, a conclusion which may be drawn from NMR results. For the AuZn alloy the electronic specific-heat coefficient (γ) is 153.4 ± 0.7 μcal/°K2 g atom and the limiting value of the Debye temperature (θ0c) is 177.0 ± 0.5 °K. For the AuIn alloy γ is 185.9 ± 0.7 μcal/°K2 g atom and θ0c is 159.1 ± 0.3 °K.