Raman scattering study of the high-temperature vibrational properties and stability of CaGeO3 perovskite

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Authors:Durben, Dan J.; Wolf, George H.; McMillan, Paul F.
Author Affiliations:Primary:
Arizona State University, Tempe, AZ, United States
Volume Title:Physics and Chemistry of Minerals
Source:Physics and Chemistry of Minerals, 18(4), p.215-223. Publisher: Springer-Verlag, Berlin-New York, Federal Republic of Germany. ISSN: 0342-1791
Publication Date:1991
Note:In English. 49 refs.; illus., incl. 2 tables
Summary:The vibrational properties of metastable CaGeO3 perovskite are investigated as a function of T using Raman scattering. Mode- assignments are derived from polarized spectra of optically oriented single crystals. Neither symmetry-breaking structural transformations nor soft-mode behaviour are revealed in the Raman spectra between room T and 650 degrees C. Only a small decrease in the local static octahedral tilt angles can be inferred from the Raman data over this T range. A Landau extrapolation of the lowest frequency Ag modes suggests that these modes become critical near 2000 degrees C, a T that is above the extrapolated zero P melting points. [Authors' abstract] [P.Br.]
Subjects:Crystals; Experimental studies; High temperature; Lower mantle; Magnesian silicates; Mantle; Melting; Oxides; Perovskite; Petrology; Physical properties; Raman spectra; Silicates; Spectra; Temperature; Calcium germanate
Abstract Numbers:92M/2633
Record ID:1997003551
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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