Low-Temperature Specific Heats inα-Phase CuSn Alloys

Low-temperature specific-heat measurements have been made between 1.5 and 4.2°K on a series of $\alpha$-phase solid-solution alloys of Sn in Cu. The dependence of $\gamma$ with $\mathfrak{z}$ (number of electrons per atom) is rather complex, the value of the initial derivative being much higher than that reported some years ago. The results are discussed in the light of recent band-structure calculations, charge-shielding effects, and Mössbauer spectra in $\alpha$-phase CuSn alloys, as well as related experimental work on low-temperature specific heats in a number of systems based on the noble metals. A rapid decrease of Debye temperature with increasing solute concentration is attributed to the exceptionally large $\frac{d\ln V}{d\mathfrak{z}}$ value.