Skip to main content

Light scattering and computer simulation studies of superionic pure and La-doped BaF2

Rammutla, K.E., Comins, J.D., Erasmus, R.M., Netshisaulu, T.T., Ngoepe, P.E., Chadwick, A.V. (2015) Light scattering and computer simulation studies of superionic pure and La-doped BaF2. Chemical Physics, 467 . pp. 6-12. ISSN 0301-0104. (doi:10.1016/j.chemphys.2015.12.004) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:60033)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://dx.doi.org/10.1016/j.chemphys.2015.12.004

Abstract

A combination of both Raman and Brillouin scattering experiments as well as Molecular Dynamics (MD) was used to study the superionic behaviour of BaF2 doped with a wide range of LaF3 concentrations (0 ? x ? 50 mol%). Raman spectroscopy reveals that for undoped BaF2 and those doped with 5% and 10% LaF3, the room temperature spectra show the usual T2g symmetry mode at 241 cm?1 whereas for those doped with 20%, 30% and 50% LaF3, the dominant Raman mode is of the Eg symmetry situated at ?263, 275 and 286 cm?1, respectively. The Raman linewidths show near linear increases with temperature followed by rapid increases above the characteristic transition temperatures (Tc), being at 1200, 850, 800, 975, 950 and 920 K for LaF3 concentrations of 0, 5, 10, 20, 30 and 50; respectively. The temperature dependence of the squares of the Brillouin frequencies (??B)2 of the LA and TA acoustic modes respectively related to elastic constants C11 and C44 showed linear decreases followed by significant deviations around the same temperatures (Tc), at which the Raman linewidths start to show substantial increases. The complementary studies using MD simulations show that the diffusion coefficients increase markedly above the same temperatures observed experimentally. The extrinsic fluorine ion trajectories were also determined from the MD simulations to better understand the mechanisms of diffusion.

Item Type: Article
DOI/Identification number: 10.1016/j.chemphys.2015.12.004
Divisions: Faculties > Sciences > School of Physical Sciences
Depositing User: Alan Chadwick
Date Deposited: 23 Jan 2017 14:55 UTC
Last Modified: 29 May 2019 18:35 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/60033 (The current URI for this page, for reference purposes)
  • Depositors only (login required):