Raman scattering study of the high-temperature vibrational properties and stability of CaGeO3perovskite

✍ Scribed by Dan J. Durben; George H. Wolf; Paul F. McMillan

• Publisher: Springer-Verlag
• Year: 1991
• Tongue: English
• Weight: 1011 KB
• Volume: 18
• Category: Article
• ISSN: 0342-1791
• DOI: 10.1007/bf00202573

✦ Synopsis

The vibrational properties of metastable Ca-GeO3 perovskite are investigated as a function of temperature using Raman scattering. Mode-assignments are derived from polarized spectra of optically oriented single crystals. Neither symmetry-breaking structural transformations nor soft-mode behavior is revealed in the Raman spectra between room temperature and 650 ~ C. Only a small decrease in the local static octahedral tilt angles can be inferred from the Raman data over this temperature range. A Landau extrapolation of the lowest frequency Ag modes suggests that these modes become critical near 2000 ~ C, a temperature that is above the extrapolated zero pressure melting point.