Structural and Magnetic Ground State of the Spinel CoFe₂O₄: A Density Functional Theory Study

We present a computational study based on the Density Functional Theory (DFT) of the magnetic and structural properties of the cobalt ferrite (CoFe₂O₄). Using ab initio calculations, the electronic structure has been analyzed, and the structural and magnetic ground states were obtained by considering the antiferromagnetic and ferromagnetic coupling in normal spinel and inverse spinel structures, taking into account different cationic distributions at the last one. Furthermore, to understand the effect of the DFT + U calculation, an analysis of the charge distribution and the change of density of states (DoS) parameters, including the bandgap and magnetic moment, was performed. In addition, a clear dependence of the magnetic moment per atom and band gap energy on the Hubbard parameter (U) was observed, with optimal values in GGA + U identified as U_Fe = 4 eV and U_Co = 4 eV. Finally, the electronic rearrangement of the outermost energy levels of the valence band (3d-orbitals) was evidenced when the Hubbard parameter was applied.