Spinel structure ${\mathrm{MnFe}}_2{\mathrm{O}}_4$ is investigated using density functional calculations. The ground state is a high spin ferrimagnet in agreement with experiment. The band structure shows a low carrier density half metal in the fully ordered state, in contrast to experimental characterizations of partially disordered samples as small band gap insulators. However, we find a strong coupling of the energy bands at the Fermi energy to the internal structural parameter u as well as strong effects on the electronic structure upon partial interchange of Fe and Mn atoms. This indicates that the insulating character may be due to Anderson localization associated with the intersite Mn-Fe disorder. This possibility is discussed in terms of the relation between other calculated properties and experimental data.

• Received 17 May 2001

DOI:https://doi.org/10.1103/PhysRevB.65.064432