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

Abstract

Magnetite (Fe3O4) 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 Fe3O4/SrTiO3 (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 Fe3O4 by a systematic analysis of the XMLD angular distribution. The local symmetry of the 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.

Tensor description of X-ray magnetic dichroism at the Fe L 2,3-edges of Fe3O4

“…The off-diagonal term differences seen are likely due to small misalignments in the orientation of the magnetization in particular given that the [0,0,1] direction is a magnetically hard direction and does not saturate with 1 T (see Fig. 13 of Appendix A) in combination with the presence of small non-cubic crystal distortion in the thin-film as we showed in earlier work (Elnaggar et al, 2020). The antisymmetric off-diagonal elements result in a…”

Stoichiometry driven tuning of physical properties in epitaxial Fe3-Cr O4 thin films

“…sites were considered for the simulations. The atomic parameters for each cation site were optimized in this work (see Supporting Information for details) and are in good agreement with the literature [38][39][40]. For all simulated spectra, the ground state was populated according to a Boltzmann distribution at 300 K. The XAS spectra were calculated by solving Green's functions in second quantization.…”