Study of atomic motion in rubidium borate glasses

Autoren:Tietz, Christoph; Holzweber, Katharina; Ross, Manuel; Stana, Markus; Sepiol, Bogdan
Abstrakt:Atomic Scale X-ray Photon Correlation Spectroscopy (aXPCS) utilizes coherent X-rays to probe the dynamics of materials on an atomic scale. It was used with great success to study atomic diffusion in crystals [1], but its application was recently extended to glasses as well [2]. Rubidium borate glasses serve as an example for fast ion-conducting alkali borate glasses and are a promising candidate for future applications in energy storage as well as in many other fields. In this work the ionic motion in rubidium borate glasses was studied via the aXPCS method.Correct data analysis of an aXPCS measurement of amorphous materials requires the knowledge of the total structure function of the diffusing atomic species, i.e. in this case the alkali ions. We used the pair distribution function (PDF) method to investigate the structure of rubidium borate glasses and Metropolis Monte Carlo simulation to extract the required partial structure factor. The parameters of a Born-Mayer-Huggins potential used by Verhoef and den Hartog [3] for structural simulations of alkali borate glasses were modified to fit the experimental scattering data.