X-Ray Absorption Spectroscopy and Computer Modelling Study of Nanocrystalline Binary Alkaline Earth Fluorides

Chadwick, Alan V. and Düvel, A. and Heitjans, P. and Pickup, D.M. and Ramos, Silvia and Sayle, D.C. and Sayle, T.X.T. (2015) X-Ray Absorption Spectroscopy and Computer Modelling Study of Nanocrystalline Binary Alkaline Earth Fluorides. IOP Conference Series: Materials Science and Engineering, 80 . 012005. ISSN 1757-899X. (doi:https://doi.org/10.1088/1757-899X/80/1/012005) (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)

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Official URL
http://doi.org/10.1088/1757-899X/80/1/012005

Abstract

Nanocrystalline samples of Ba1-xCaxF2 prepared by high-energy milling show an unusually high F? ion conductivity, which exhibit a maximum in the magnitude and a minimum in the activation energy at x = 0.5. Here, we report an X-ray absorption spectroscopy (XAS) at the Ca and Sr K edges and the Ba L3 edge and a molecular dynamics (MD) simulation study of the pure and mixed fluorides. The XAS measurements on the pure binary fluorides, CaF2, SrF2 and BaF2 show that high-energy ball-milling produces very little amorphous material, in contrast to the results for ball milled oxides. XAS measurements of Ba1-xCaxF2 reveal that for 0 < x <1 there is considerable disorder in the local environments of the cations which is highest for x = 0.5. Hence the maximum in the conductivity corresponds to the composition with the maximum level of local disorder. The MD calculations also show a highly disordered structure consistent with the XAS results and similarly showing maximum disorder at x = 0.5.

Item Type: Article
Subjects: Q Science > QD Chemistry > QD478 Solid State Chemistry
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Silvia Ramos
Date Deposited: 28 Apr 2015 10:31 UTC
Last Modified: 10 Dec 2017 22:17 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/48084 (The current URI for this page, for reference purposes)
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