Thermal expansion in Cr:LiSrGaF6 |
| |
Authors: | Andrzej Grzechnik Zunbeltz Izaola Azcona Karen Friese |
| |
Affiliation: | a Departamento de Física de la Materia Condensada, Universidad del País Vasco, Apdo. 644, Bilbao E-48080, Spain b Forschungszentrum Karlsruhe GMBH, Institute for Synchrotron Radiation, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany |
| |
Abstract: | High-temperature behaviour of LiSrGaF6 doped with 1.5 at.% of Cr3+ was studied with high-resolution synchrotron angle-dispersive X-ray powder diffraction in the temperature range 298-539 K. No phase transitions were detected. The origin of negative thermal expansion along the c axis is discussed based on the temperature dependencies of structural parameters and octahedral distortions obtained with the Rietveld method. The SrF6 slab contracts with increasing temperatures because of the diminishing F-Sr-F octahedral angles without any changes in the F-F octahedral edges not only around strontium but also around lithium and gallium. At the same time, the angular distortions of the SrF6 octahedra are largely diminished. Such a behaviour is discussed in comparison with the thermal expansion of LiCaAlF6 and LiSrAlF6. |
| |
Keywords: | A Fluorides A Optical materials C X-ray diffraction D Crystal structure D Thermal expansion |
本文献已被 ScienceDirect 等数据库收录! |