Abstract
Electronic structure of manganese ferrite is calculated using the density functional theory. Partially inverted structure with the inversion parameter y=0.0625 is considered, using four different supercells (Mn15Fe)[Fe31Mn]O64 that differ in relative position of FeA and MnB.
The crystal structure was optimized by minimizing the forces acting on the atoms. The spin magnetic moments m of Mn and Fe ions depend to some extent on their position in the supercell, but we found that in all cases m(MnB) is considerably smaller (by approx. one Bohr magneton) than m(MnA).
This indicates strongly that the formal valence of MnB is 3+. Trivalent manganese in an octahedral position is expected to exhibit a Jahn-Teller effect and corresponding analysis was performed.
No pronounced localization of the extra electron in the octahedral sublattice that would represent the Fe2+ ion was found.