Sub-micron spatial resolution of configurational disorder in high entropy oxides

We aim to produce a comprehensive structural model for spinel-type high entropy oxides (HEOs), including possible selective ion clustering. This goal implies characterising the oxidation state, crystal field environment, and distribution of ions, with sub-micron spatial resolution, in the (CrMnFeCoNi)0.6O4 system. We have previously conducted X-ray magnetic circular dichroism on (CrMnFeCoNi)0.6O4, from which we know the ions are inhomogeneously distributed across the tetrahedral and octahedral sites of the spinel host, in contrast to the presumed random distribution in an ideal HEO. The results for (CrMnFeCoNi)0.6O4 will be compared to a reference rocksalt-type HEO, where only octahedral coordination is possible and random distribution of the ions is realised. This study aims to improve the structural understanding of spinel-type HEOs, to better tailor their functional properties which, due to their enhanced stability, are of technological interest in catalysis and energy storage.