High-resolution STEM-EELS provides information about the composition of crystalline materials at the atomic scale, though a reliable quantitative chemical analysis is often hampered by zone axis conditions, where neighbouring atomic column intensities contribute to the signal at the probe position. In this work, we present a procedure to determine the concentration of two elements within equivalent atomic columns from EELS elemental maps – in our case barium and lanthanum within the A-sites of Ba 1.1La 1.9Fe 2O 7, a second order Ruddlesden-Popper phase. We took advantage of the large changes in the elemental distribution from column to column and introduced a technique, which substitutes inelastic scattering cross sections during the quantification step by using parameters obtained from the actual experiment. We considered channelling / de-channelling effects via inelastic multislice simulations and were thereby able to count occupancies in each atomic column. The EELS quantification results were then used as prior information during the Rietveld refinement in XRD measurements in order to differentiate between barium and lanthanum.
Bibliographische NotizFunding Information:
This work was supported by the Austrian Research Promotion Agency FFG [grant No. 853538 ], the Klima- und Energiefonds within the program ‘Energieforschung (e!MISSION)’ [grant No. 871659 ], the European Union Horizon 2020 programme [grant No. 823717–ESTEEM3 ] and the Austrian Science Fund FWF [grant No. I4309-N36 ]. The authors acknowledge financial support by the ‘Zukunftsfonds Steiermark‘ for the purchase of the K2-camera through the ‘ASTEM upgrade‘ project (grant No. 9016).
© 2022 The Authors