Crystal structure and specific heat of GdCuGe

A single crystal study of GdCuGe revealed full copper–germanium ordering: NdPtSb type, space group P63mc  , a=423.2(1)a=423.2(1), c=753.7(2)pm, wR2=0.0443wR2=0.0443, 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.

Graphical abstractCrystal structure of GdCuGe. The gadolinium, copper, and germanium atoms are drawn as medium gray, black filled, and open circles, respectively. The two-dimensional [CuGe] networks are emphasized.Figure optionsDownload full-size imageDownload as PowerPoint slide