Low-Temperature Specific Heats ofAgSnAlloys

The specific heats of pure Ag and $\mathrm{Ag}\mathrm{Sn}$ alloys up to 8 at.% Sn have been measured between 2 and 4°K with a precision generally better than ½%. For pure Ag, the result is $\gamma =(0.646\mathrm{}\pm 0.005)$ mJ ${\mathrm{mol}}^{-1\mathrm{}}$°${\mathrm{K}}^{-2\mathrm{}}$, and the Debye temperature is (225.5±0.5)°K, both in good agreement with one group of previous workers. The electronic coefficient $\gamma$ varies linearly versus electron-per-atom ratio $\frac{e}{a}$ at the rate $\frac{d\left(\ln \gamma \right)}{d\left(\frac{e}{a}\right)}=0.22\mathrm{}\pm 0.06$, in agreement with the $\mathrm{Ag}\mathrm{Cd}$ data of Montgomery and Pells. The Debye temperature decreases on alloying, following a common curve versus $\frac{e}{a}$ with the $\mathrm{Ag}\mathrm{Cd}$ results. The calorimetric method is unusual; repeated measurements are made at 2, 3, and 4°K only, and considerable thermal conductance is allowed between the sample and a cold reservoir.