Extracting Interface Correlations from the Pair Distribution Function of Composite Materials

Abstract

\n \n \n Using a non-negative matrix factorisation (NMF) approach,\nwe show how the pair distribution function (PDF) of complex\nmixtures can be deconvolved into the contributions from\nthe individual phase components and also the interface between phases. Our focus is on the model system Fe||Fe3O4.\nWe establish proof-of-concept using idealised PDF data\ngenerated from established theory-driven models of the\nFe||Fe3O4 interface. Using X-ray PDF measurements for\ncorroded Fe samples, and employing our newly-developed\nNMF analysis, we extract the experimental interface PDF\n(‘iPDF’) for this same system. We find excellent agreement\nbetween theory and experiment. The implications of our\nresults in the broader context of interface characterisation\nfor complex functional materials are discussed.\n\n \n \n