Direct evidence for an interdiffused intermediate layer in bi-magnetic core–shell nanoparticles

International audienceCore–shell nanoparticles attract continuously growing interest due to their numerous applications, whichare driven by the possibility of tuning their functionalities by adjusting structural and morphologicalparameters. However, despite the critical role interdi!used interfaces may have in the properties, theseare usually only estimated in indirect ways. Here we directly evidence the existence of a 1.1 nm thick(Fe,Mn)3O4 interdi!used intermediate shell in nominally g-Fe2O3–Mn3O4 core–shell nanoparticles usingresonant inelastic X-ray scattering spectroscopy combined with magnetic circular dichroism (RIXS-MCD).This recently developed magneto-spectroscopic probe exploits the unique advantages of hard X-rays(i.e., chemical selectivity, bulk sensitivity, and low self-absorption at the K pre-edge) and can beadvantageously combined with transmission electron microscopy and electron energy loss spectroscopyto quantitatively elucidate the buried internal structure of complex objects. The detailed information onthe structure of the nanoparticles allows understanding the in"uence of the interface quality on themagnetic properties