Electronic structure and magnetic properties of fete, bifeo₃, srfe₁₂o₁₉ and srcotife₁₀o₁₉ compounds

The electronic energy structures and magnetic properties of iron-based compounds with group VI elements (FeTe, BiFeO₃, SrFe₁₂O₁₉ and SrCoTiFe₁₀O₁₉) are studied using the density functional theory (DFT) methods. Manifestations of different types of chemical bonds in magnetism of these compounds are studied theoretically. Calculations of electronic structures of these systems are performed, by using the generalized gradient approximation (GGA) for the description of the exchange and correlation effects within DFT. For SrFe₁₂O₁₉ and SrCoTiFe₁₀O₁₉ hexaferrites, the GGA + U method is also employed to deal with strongly correlated 3d-electrons. The calculations have revealed distinctive features of the electronic structure of the investigated iron-based compounds with strongly correlated 3d-electrons, which can be responsible for their peculiar structural and magnetic properties.