Investigation of the superionic behaviour of BaF 2 ( x mol% LaF 3 ) by raman and brillouin scattering and molecular dynamics simulations
| Autor: | J. D. Comins, P. E. Ngoepe, T. T. Netshisaulu, K. E. Rammutla, Rudolph M. Erasmus, Alan V. Chadwick |
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| Rok vydání: | 2002 |
| Předmět: |
Nuclear and High Energy Physics
Radiation business.industry Chemistry Analytical chemistry Condensed Matter Physics Light scattering Brillouin zone symbols.namesake Optics Brillouin scattering Molecular vibration symbols General Materials Science business Spectroscopy Raman spectroscopy Raman scattering Solid solution |
| Zdroj: | Radiation Effects and Defects in Solids. 157:783-788 |
| ISSN: | 1029-4953 1042-0150 |
| Popis: | High temperature Raman and Brillouin light scattering experiments have been combined with molecular dynamics simulations to provide a comprehensive study of the superionic state of BaF 2 ( x v mol% LaF 3 ) over a particularly wide range of LaF 3 dopant concentrations from x =0 to 50. Room temperature Raman spectra for x =0, 5 and 10 show the usual T 2g symmetry mode at 241 v cm m 1 , but for samples with x =20, 30 and 50 the dominant Raman mode is at higher frequencies and of E g symmetry. The temperature dependence of the Raman line-widths show initial near linear increases followed by substantial increases above temperatures ( T c ) at 1200, 850, 800, 975, 950 and 920 v K for x =0, 5, 10, 20, 30 and 50. In the Brillouin scattering experiments, the acoustic modes respectively related to elastic constants C 11 and C 44 initially showed a quasi-linear decrease in frequency with increasing temperature. Above the same characteristic values of T c , where the Raman line-widths show marked increases, there are... |
| Databáze: | OpenAIRE |
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