Probing the local distortion of Fe sites in Fe3O4 thin films using enhanced symmetry selection in XMLD

Abstract

Magnetite (${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$) thin-films are among the most stimulating systems for electronic applications, in particular given that their electric and magnetic properties can be controlled by substrate strain. Here we investigate the electronic structure of a 38 nm ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}/{\mathrm{SrTiO}}_{3}\phantom{\rule{4pt}{0ex}}(001)$ thin-film by a unique set of x-ray magnetic linear dichroism (XMLD) measurements. We show that it is only possible to uncover the orbital character of the Fe sites in ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ by a systematic analysis of the XMLD angular distribution. The local symmetry of the ${\mathrm{Fe}}^{2+}$ B site in the thin-film is found to be trigonally distorted. Our results highlight that the combination of state-of-the-art XMLD measurements and theoretical simulations is indispensable for investigating the electronic structure of oxide thin-films and heterostructures.