Electronic structure and x-ray magnetic circular dichroism in the multiferroic oxide h−YbFeO3

Abstract

Hexagonal ferrites ($h\text{\ensuremath{-}}R{\mathrm{FeO}}_{3}$, $R$ = Sc, Y, Ho-Lu) have recently been identified as a new family of multiferroic complex oxides. We study electronic and magnetic properties of $h\text{\ensuremath{-}}{\mathrm{YbFeO}}_{3}$ ferrite within the density-functional theory using the generalized gradient approximation (GGA) with consideration of strong Coulomb correlations $(\mathrm{GGA}+U)$ in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. The $4f$ electrons of Yb are explicitly treated as valence electrons. The x-ray absorption spectra and x-ray magnetic circular dichroism (XMCD) at the Yb ${M}_{4,5}$, Fe ${L}_{2,3}$, and O $K$ edges were investigated theoretically. The calculated results are in good agreement with experimental data. We found that the $\mathrm{GGA}+U$ approach with Hubbard ${U}_{\mathrm{eff}}=6.1\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$ and 3.3 eV for Yb and Fe, respectively, well describes the XMCD spectra at the Yb ${M}_{4,5}$, Fe ${L}_{2,3}$, and O $K$ edges.