Lattice dynamics and high‐pressure properties of K‐ionic conducting system KNbTeO6

In the present work, we report results of high‐pressure Raman scattering spectroscopy, on the ionic conducting system KNbTeO6, as well as lattice dynamics calculations for this compound. From lattice dynamics calculation, we were able to do a definite assignment of modes for this system taking into...

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Veröffentlicht in:Journal of Raman spectroscopy 2020-12, Vol.51 (12), p.2517-2524
Hauptverfasser: Paraguassu, Waldeci, Knyazev, Alexander V., Corrêa, Gregório B., Blokhina, A.G., Demidov, D.N., Ghosh, Angsula
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Sprache:eng
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Zusammenfassung:In the present work, we report results of high‐pressure Raman scattering spectroscopy, on the ionic conducting system KNbTeO6, as well as lattice dynamics calculations for this compound. From lattice dynamics calculation, we were able to do a definite assignment of modes for this system taking into account the disorder caused by random K occupation and shared occupation of Nb and Te ions. On the basis of the theoretical results, we discuss the changes observed in the high‐pressure Raman spectra. We report a transformation occurring around 4.7 GPa, attributed it to a structural phase transition. The Raman spectra during the decompression process reveals that all changes undergone by the structure are reversible, and the Raman spectrum recovers its original signature. K‐ionic conducting system KNbTeO6 where investigated by high‐pressure Raman scattering spectroscopy and lattice dynamics calculations. A definite assignment of modes, as well the set of interacting forces, was proposed, taking into account the disorder, caused by random K occupation and shared occupation of Nb and Te ions. The phase transition observed at 4.7 GPa is market by the presence of a low‐energy soft‐like mode. The changes undergone by the structure are reversible.
ISSN:0377-0486
1097-4555
DOI:10.1002/jrs.6018