Abstract
The electrical and magnetic properties of manganese ferrite (MnFe₂O₄) are calculated with the density-functional theory (DFT) method for both normal and inverse spinel structures. The exchange functional is chosen to be a mixture of Becke exchange and Fock exchange with variable weight (w). The exchange integrals JAB (the exchange integral between the nearest-neighbor A and B sites) and JBB (the exchange integral between nearest-neighbor B sites) are calculated by substituting the total energies of different magnetic ground states into the Heisenberg model. The calculated value of JAB is in agreement with the experimental values measured by neutron diffraction and NMR. Also, the parameters U (Coulomb repulsion energy), Δ (charge-transfer energy), and EG (band gap) are extracted from the density of states (DOS) and plotted versus w. Our calculated band gap shows that MnFe₂O₄ is a complex insulator, in contrast to previous local spin-density approximation and generalized gradient approximation calculations, which showed it to be half metallic.
Keywords
manganese ferrite, density functional theory method, DFT, exchange integrals, electronic structure, MnFe₂O₄, Becke exchange, Fock exchange, JAB, JBB, Heisenberg model, Coulomb repulsion energy, charge transfer energy, band gap
Subject Categories
Density functionals, Spinel
Disciplines
Electromagnetics and photonics
Publisher
American Physical Society
Publication Date
11-1-2002
Rights Information
Copyright 2002 American Physical Society
Rights Holder
American Physical Society
Permanent URL
Recommended Citation
Zuo, X. and Vittoria, C., "Calculation of exchange integrals and electronic structure for manganese ferrite" (2002). Electrical and Computer Engineering Faculty Publications. Paper 26. http://hdl.handle.net/2047/d20002196
Click button above to open, or right-click to save.
Notes
Originally published in Physical Review B 66, 184420 (2002). doi 10.1103/PhysRevB66.184420 (http://link.aps.org/doi/10.1103/PhysRevB66.184420).