Reverse Monte Carlo investigation of the temperature dependent deuterium distribution in ZrCr2D4

Short-range correlations in ZrCr2D4 have been investigated with total neutron scattering and Reverse Monte Carlo (RMC) modelling. Data were collected for the deuteride with a disordered deuterium lattice at 298 K, a partly ordered deuterium lattice at 248 K and a fully ordered deuterium lattice at 150 K. Short-range order (SRO) prevents occupation of interstitial sites closer than 2 Å from deuterium atoms in the disordered and partly ordered samples in agreement with the Switendick criterion and earlier investigations. The deuterium configurations at 298 and 248 K resemble those found in the fully ordered phase at length scales up to about 4 Å. There is no appreciable difference in the short-range deuterium correlations or the extent of the SRO at 248 K as compared to at 298 K. The differences and similarities with the previously investigated compound VD0.8 are discussed.