First order phase transition of Li3ThF7at 281 K: A comparative study between EPR and Raman scattering
| Autor: | J. Y. Gesland, R. L. Moreira, C. J. Franco, Maurício V. B. Pinheiro, M. A. S. Oliveira, K. J. Guedes, K. Krambrock |
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| Rok vydání: | 2001 |
| Předmět: |
Nuclear and High Energy Physics
Phase transition Radiation Chemistry Ionic bonding Condensed Matter Physics law.invention symbols.namesake Crystallography Nuclear magnetic resonance law symbols Ionic conductivity General Materials Science Orthorhombic crystal system Raman spectroscopy Electron paramagnetic resonance Raman scattering Monoclinic crystal system |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1029-4953 1042-0150 |
| Popis: | Electron Paramagnetic Resonance (EPR) and Raman Spectroscopy were used to study the low temperature phase transition of pulled Li 3 ThF 7 single crystals, occurring at 281 K. In both cases, the room temperature spectra were very broad, owing to the statistical disorder and high ionic mobility of the lithium ions, which occupy only 3/4 of their structural sites. The results are compatible with a first order ferroelastic transition from the room temperature orthorhombic D 2h 22 phase to a monoclinic C 2h (x) one. The symmetry rules are well respected assuming a model with four lithium ions in average per chemical formula. The EPR spectra show also the appearing of additional ferroelastic domains. |
| Databáze: | OpenAIRE |
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