Low-temperature X-ray diffraction studies of near-equiatomic VRu alloys

A crystallographic transition of the ordered near-equiatomic VRu alloys has been observed between 360 and 110 K. This cubic-to-tetragonal distortion occurs over a temperature interval commensurate with the observed anomalies in electrical resistivity, magnetic susceptibility, and the Knight shift. The transition involves a 1.4% expansion in volume for V0.50Ru0.50. This expansion is very nearly temperature independent between 300 and 110 K. The volume change for V0.51Ru0.49 at 110 K is 1.5%. For both compounds the CsCl-type ordering is approximately 100%.