Low-Temperature Specific Heats ofα−CuSnandα−CuZnAlloys

The specific heats of copper, of five copper-tin alloys of up to 6.2 at.% tin in copper, and of one alloy of 2.7 at.% zinc in copper have been measured between 2°K and 4°K. The electronic specific-heat coefficient $\gamma$ for the copper-tin alloys can be expressed as a function of electron-per-atom ratio $\frac{e}{a}$ by the relation $\gamma =(0.700\mathrm{}\pm 0.003)+(0.17\pm 0.04)$ ($\frac{e}{a}-1\mathrm{}$) in units of mJ ${\mathrm{mole}}^{-1\mathrm{}}$ °${\mathrm{K}}^{-2\mathrm{}}$. The value of $\gamma =0.705\mathrm{}$ for the one $\mathrm{Cu}\mathrm{Zn}$ alloy is consistent with the above relation. The value of $\frac{d\left(\ln \gamma \right)}{d\left(\frac{e}{a}\right)}=0.24\mathrm{}\pm 0.06$ agrees with $\frac{d\left(\ln \gamma \right)}{d\left(\frac{e}{a}\right)}=0.33\mathrm{}\pm 0.10$ calculated from earlier measurements on $\mathrm{Cu}\mathrm{Zn}$ alloys by Veal and Rayne. Both of these results disagree with a value of $\frac{d\left(\ln \gamma \right)}{d\left(\frac{e}{a}\right)}=-0.94\mathrm{}$ obtained from measurements on $\mathrm{Cu}\mathrm{Zn}$ alloys by Massalski and Isaacs. The Debye temperature is a linearly decreasing function of $\frac{e}{a}$ as expressed by the relation ${\Theta }_{\mathrm{D}}=(344.7\mathrm{}\pm 0.8)°\mathrm{K}-(188\mathrm{}\pm 9)(\frac{e}{a}-1)°\mathrm{K}$. All errors are 95% confidence limits.