PNNL

Abstract

The structural and energetic properties of A2Hf2O7 (A = Dy, Ho, Er) compounds have been investigated by means of ab initio total energy calculations. For Er2Hf2O7 the defect fluorite structure is predicted to be more stable than pyrochlore structure, agreeing well with previous experimental [J. Inorg. Nucl. Chem. 31, (1969) 2367, J. Less-Common Met. 14 (1968) 435] and theoretical [J. Am. Ceram. Soc. 85 (2002) 2139] investigations. In contrast to Er2Hf2O7 pyrochlore, Dy2Hf2O7 and Ho2Hf2O7 prefer pyrochlore structures, which is consistent with the recently experimental observations of Dy2Hf2O7 compound [J. Solid State Chem. 179 (2006) 1990].