Specific heat of ordered equiatomic InMg, CuPt, and CuAu I below 30 K

Abstract

The results of specific heat measurements on ordered In −51.67 at.% Mg are presented. A superconducting transition was seen at about 0.95 K. In the normal state, the lattice specific heat varies in the usual way with temperature, i.e., the Debye temperature initially decreases with increasing temperature. This behavior was also seen in ordered equiatomic CuPt but in ordered equiatomic CuAu I the Debye temperature first goes through a maximum before decreasing to the usual minimum. The structure of all three alloys consists of alternating layers of different mass and it was initially supposed that the CuAu I result was a two-dimensional effect. However, the more recent and normal results on InMg and CuPt make this improbable and it appears that the CuAu I result is related to the behavior of pure gold which is itself anomalous.