Premium
Variation of cation distribution with temperature and its consequences on thermal expansion for Ca 3 Eu 2 (BO 3 ) 4
Author(s) -
Kosyl Katarzyna M.,
Paszkowicz Wojciech,
Shekhovtsov Alexey N.,
Kosmyna Miron B.,
Antonowicz Jerzy,
Olczak Adam,
Fitch Andrew N.
Publication year - 2020
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520620006757
Subject(s) - europium , thermal expansion , anisotropy , rietveld refinement , lattice constant , materials science , lattice (music) , diffraction , thermal , crystallography , crystal structure , analytical chemistry (journal) , chemistry , thermodynamics , metallurgy , physics , optics , luminescence , optoelectronics , chromatography , acoustics
The structure of calcium europium orthoborate, Ca 3 Eu 2 (BO 3 ) 4 , was determined using high‐resolution powder X‐ray diffraction data collected at the ID22 beamline (ESRF) under ambient conditions, as well as at high temperature. Rietveld refinement allowed determination of the lattice constants and structural details, including the Ca/Eu ratios at the three cationic sites and their evolution with temperature. Clear thermal expansion anisotropy was found, and slope changes of lattice‐constant dependencies on temperature were observed at 923 K. Above this temperature the changes in occupation of the Ca/Eu sites occur, exhibiting a tendency towards a more uniform Eu distribution over the three Ca/Eu sites. Possible structural origins of the observed thermal expansion anisotropy are discussed.