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

12th Europhysical Conference on Defects in Insulating Materials

材料科学;物理学

Chadwick, A.V.^1 ; Düvel, A.^2 ; Heitjans, P.^2 ; Pickup, D.M.^1 ; Ramos, S.^1 ; Sayle, D.C.^1 ; Sayle, T.X.T.^1

School of Physical Sciences, University of Kent, Canterbury, Kent

CT2 7NH, United Kingdom^1

Institute of Physical Chemistry and Electrochemistry, Gottfried Wilhelm Leibniz University Hannover, Callinstrasse 3a, Hannover

D-30167, Germany^2

关键词: Alkaline earth fluorides;    Computer modelling;    Disordered structures;    High-energy ball milling;    Ion conductivities;    Local environments;    Molecular dynamics simulations;    Nanocrystalline sample;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/80/1/012005/pdf
DOI  :  10.1088/1757-899X/80/1/012005

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Nanocrystalline samples of Ba1-xCaxF2prepared 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 L3edge and a molecular dynamics (MD) simulation study of the pure and mixed fluorides. The XAS measurements on the pure binary fluorides, CaF2, SrF2and BaF2show that high-energy ball-milling produces very little amorphous material, in contrast to the results for ball milled oxides. XAS measurements of Ba1-xCaxF2reveal that for 0