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Raman scattering study of a phase transition in tantalum pentoxide

✍ Scribed by P. S. Dobal; R. S. Katiyar; Y. Jiang; R. Guo; A. S. Bhalla

Publisher: John Wiley and Sons
Year: 2000
Tongue: English
Weight: 98 KB
Volume: 31
Category: Article
ISSN: 0377-0486
DOI: 10.1002/1097-4555(200012)31:12<1061::aid-jrs644>3.0.co;2-g

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✦ Synopsis

Ta 2 O 5 ceramics and crystals were prepared and analyzed using Raman spectroscopy in the temperature range 25-873 K. The low-energy phonon bands (n < 100 cm -1 ) of Ta 2 O 5 are assigned to external modes originating from the interaction between different Ta polyhedra and TaO n 5-2n -Ta 6 O 12 6Y clusters. The temperature and polarization dependence of external modes suggests the existence of clusters in the material. A softening of the low-energy bands was observed with increasing temperature. The spectral evolutions show a soft modederived second-order monoclinic to orthorhombic phase transition at about 600 K in Ta 2 O 5 .

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