1 Geology, Department of Geosciences and Natural Resource Management, Faculty of Science, Københavns Universitet2 Departamento F´isica Materia Condensada, Facultad de Ciencia y Tecnolog´ia, Universidad del3 Institut f¨ur Mineralogie/Petrographie, Leopold-Franzens-Universit¨at, Innrain 52, A-60204 SNBL/ESRF, BP220, F-38043 Grenoble C´edex, France5 Universit´e du Maine, Cristallogenese, F-72025 Le Mans C´edex, France6 Geology, Department of Geosciences and Natural Resource Management, Faculty of Science, Københavns Universitet
KY3F10 (Fm¯3m, Z = 8) is an anion-excess fluorite-related superstructure, which is employed as a room-temperature laser, when doped with rare-earths. Earlier conductivity measurements have revealed two thermally activated processes below and above 600 K. In this work we studied the high-temperature behaviour of KY3F10 in the temperature range from 293 K up to 800 Kat ambient pressure using x-ray powder and single crystal diffraction. No structural phase transition is observed in this temperature range and the structure determinations reveal that the change of structural parameters, interatomicdistances, and angles with temperature is very small. A prominent maximum observed in the difference Fourier maps, which corresponds to the centre of an empty F8 cube, might be one of the interstitial sites involved in the conduction mechanism.
Journal of Physics: Condensed Matter, 2006, Vol 18