کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1476403 | 1510146 | 2007 | 4 صفحه PDF | دانلود رایگان |

The phase transition sequence of sodium tantalate (NaTaO3) ceramic samples has been investigated by Raman spectroscopy, from room temperature up to 640 °C. At room temperature, NaTaO3 shows an orthorhombically distorted perovskite structure belonging to the Pbnm space group. Raman and infrared vibrational spectra at 20 °C are in relative good agreement with group theory predictions for this group. At high temperatures, NaTaO3 shows three phase transitions, in the sequence Pbnm (∼450 °C) Cmcm (∼560 °C) P4/mbm (∼620 °C) Pm3¯m. The Raman spectra for the two intermediate high temperature phases showed a decreasing of the number of the active modes, accompanied by band broadening, and were well compatible with structural symmetry increasing at higher temperatures.
Journal: Journal of the European Ceramic Society - Volume 27, Issues 13–15, 2007, Pages 3683–3686