Search results for "Lattice-Dynamics"
showing 3 items of 3 documents
Characterization of Flux-Grown SmxNd1–xVO4 Compounds and High-Pressure Behavior for x = 0.5
2019
The crystal structure and the vibrational and optical characteristics of flux-grown mixed lanthanide vanadate compounds SmxNd1–xVO4 (x = 0, 0.1, 0.25, 0.5, 0.75 and 1) are reported. A linear, monot...
Anomální Ramanovy módy v teluridech
2021
[EN] Two anomalous broad bands are usually found in the Raman spectrum of bulk and 2D Te-based chalcogenides, which include binary compounds, like ZnTe, CdTe, HgTe, GaTe, GeTe, SnTe, PbTe, GeTe2, As2Te3, Sb2Te3, Bi2Te3, NiTe2, IrTe2, and TiTe2, as well as ternary compounds, like GaGeTe, SnSb2Te4, SnBi2Te4, and GeSb2Te5. Many different explanations have been proposed in the literature for the origin of the anomalous broad bands in tellurides, usually located between 119 and 145 cm(-1). They have been attributed to the intrinsic Raman modes of the sample, to oxidation of the sample, to the folding of Brillouin-edge modes onto the zone center, to the existence of a double resonance, like that …
X-ray absorption spectroscopy study of local dynamics and thermal expansion in ReO3
2015
The thermal expansion of polycrystalline ${\mathrm{ReO}}_{3}$ is studied in vacuum by x-ray diffraction from 300 to 600 K and by extended x-ray absorption fine structure (EXAFS) at the Re ${L}_{3}$ edge from 30 to 600 K. A detailed EXAFS analysis is presented up to the sixth coordination shell around Re. The crystal thermal expansion is weak throughout the explored range, negative below 100 K, positive from 150 to 500 K, and negative again above 500 K. The analysis of mean square relative displacements obtained by EXAFS and of mean square displacements available from x-ray and neutron diffraction measurements confirms the presence of significant static disorder in the investigated samples. …