A method for a column-by-column EELS quantification of barium lanthanum ferrate

High-resolution STEM-EELS provides information about the composition of crystalline materials at the atomicscale, though a reliable quantitative chemical analysis is often hampered by zone axis conditions, whereneighbouring atomic column intensities contribute to the signal at the probe position. In this work, we present aprocedure to determine the concentration of two elements within equivalent atomic columns from EELSelemental maps – in our case barium and lanthanum within the A-sites of Ba1.1La1.9Fe2O7, a second orderRuddlesden-Popper phase. We took advantage of the large changes in the elemental distribution from column tocolumn and introduced a technique, which substitutes inelastic scattering cross sections during the quantificationstep by using parameters obtained from the actual experiment. We considered channelling / de-channellingeffects 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 XRDmeasurements in order to differentiate between barium and lanthanum.