A Raman study of the superionic behaviour of CaF 2 crystals containing trivalent lanthanide ions

Autor: J. D. Comins, Marjorie Mujaji
Rok vydání: 2007
Předmět:
Zdroj: physica status solidi c. 4:851-855
ISSN: 1610-1642
1862-6351
DOI: 10.1002/pssc.200673772
Popis: Raman scattering studies of the T2g mode in an undoped CaF2 crystal and in CaF2 crystals separately doped with 10% of Tb3+, Tm3+ and Nd3+ ions as well as 10% to 20% of La3+ ions, in the temperature range 295 K – 1400 K, are presented. The linewidth (FWHM) of the T2g peak is found to increase almost linearly with temperature, up to the transition onset temperature of ∼1025 K for the undoped and between 850 K and 975 K for the 10% doped crystals. Thereafter linewidth increases are steeper in all cases. Further, as the temperature of each sample is raised, the peak position drifts to lower energies. The 15% and 20% La3+- doped samples show the same behaviour as for 10% except for slightly lower transition temperature and peak energy. Interstitial F– ions and lattice distortions are responsible for these effects. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Databáze: OpenAIRE
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