Electronic structure and properties of strontium ferrite Sr<Subscript>3</Subscript>Fe<Subscript>2</Subscript>O<Subscript>6</Subscript>

The electronic structure of strontium ferrite Sr<Subscript>3</Subscript>Fe<Subscript>2</Subscript>O<Subscript>6</Subscri pt> was calculated using the tight-binding linear muffin-tin orbital method (TB LMTO) in the local spin density approximation of density functional theory with Coulomb correlations correction (LSDA+U). The semiconducting character of the spectrum with charge transfer energy gap of 1.82 eV was obtained in reasonably good agreement with experimental data. The iron ions are found to be in the high spin state. The calculated value of the local spin magnetic moment of Fe<Superscript>3+</Superscript> ion is 3.94 μ<Subscript>B</Subscript> which is not typical for trivalent iron ion in the high spin state. It is shown that the strong hybridization between Fe3d and O2p orbitals favors the d<Superscript>6</Superscript> L configuration of Fe<Superscript>3+</Superscript> ion, where L is a hole in the oxygen p shell. The mechanism of oxygen transport in ferrite is discussed basing on the total energy calculations of the different spatial configurations of oxygen vacancies. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2006