Crystal structure and specific heat of GdCuGe

A single crystal study of GdCuGe revealed full copper–germanium ordering: NdPtSb type, space group P63mc, image, image, image, 414 F2 values and 10 variables. The copper and germanium atoms build up two-dimensional networks of ordered [Cu3Ge3] hexagons with Cu–Ge distances of 244 pm. Consecutive [Cu3Ge3] layers are rotated by 60° around the perpendicular c-axis with respect to each other. The [Cu3Ge3] hexagons show a weak puckering. Heat capacity measurements on the polycrystalline sample of GdCuGe establishes antiferromagnetic ordering around 14 K in agreement with reports in the literature. The curves of heat capacity measured in different applied fields crosses each other at two well-defined points exhibiting a behavior usually associated with heavy fermion compounds. The results of the structural analysis and heat capacity measurements are discussed in the light of these interesting observations for a gadolinium intermetallic.