Heat Capacity ofγ-CuZn Alloys below 4.2°K

Low-temperature heat capacity measurements have been made on a series of high-purity specimens covering the entire $\gamma$ phase of the Cu-Zn system. The electronic heat capacity decreases rapidly with increasing zinc concentration, thereby lending support to the hypothesis that the $\gamma$ brasses are electron compounds. An excellent fit to the data may be obtained by assuming that the Fermi surface of these alloys is spherical and makes contact with the large Brillouin zone of the $\gamma$-brass structure. The Debye temperature of the alloys is 433°K and is approximately independent of zinc concentration.