SAIP2013

Investigation of Phase Transitions in Tungsten Trioxide

9 Jul 2013, 11:10

20m

Oral Presentation Track G - Theoretical and Computational Physics Theoretical

Speaker

Mr Malcolm Govender (CSIR)

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD)?

PhD

Abstract content <br> &nbsp; (Max 300 words)

It is well known that tungsten trioxide shows temperature-dependant structural phases, starting from a mixture of triclinic-monoclinic symmetry at room temperature, and transitions to tetragonal symmetry above 900^oC. However, the order of these transitions are not well understood which can predict if the phase transition is reversible. The allowed symmetries of the polymorphic modifications after the phase transitions are determined using group theoretical arguments in the framework of the Landau-Lifshitz theory of second-order phase transitions. The theoretical calculations predicted that the phase transition to the highest temperature phase is second-order and is therefore reversible, and this was verified using the experimental techniques of x-ray diffraction, Raman spectroscopy and thermogravimetric analysis.

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

No

Main supervisor (name and email)<br>and his / her institution

Herbert W. Kunert, Herbert.Kunert.up.ac.za
Unviversity of Pretoria

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes