Intrinsic and extrinsic x-ray absorption effects in soft x-ray diffraction from the superstructure in magnetite

Abstract

We studied the ($00\frac{1}{2}$) diffraction peak in the low-temperature phase of magnetite (${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$) using resonant soft x-ray diffraction at the $\mathrm{Fe}\ensuremath{-}{L}_{2,3}$ and $\mathrm{O}\ensuremath{-}K$ resonances. We studied both molecular-beam-epitaxy grown thin films and in situ cleaved single crystals. From the comparison, we have been able to determine quantitatively the contribution of intrinsic absorption effects, thereby arriving at a consistent result for the ($00\frac{1}{2}$) diffraction peak spectrum. Our data also allow for the identification of extrinsic effects, e.g., for a detailed modeling of the spectra in case a dead surface layer is present that is only absorbing photons but does not contribute to the scattering signal.