Structural, electronic and magnetic properties of inverse spinel NiFe2O4: DFT + U investigation

We have used ab initio density functional theory (DFT) to explore the structural, mechanical, electronic and magnetic properties of inverse spinel NiFe2O4. The ultra-soft pseudopotential method parametrized under generalized gradient approximation (GGA) for the exchange-correlation functional with Hubbard correction (GGA + U) was applied. The equilibrium lattice parameter was estimated to be 8.4620 A and the 3 independent elastic constants C-11, C-12 and C(44 )were found to be 304.12 GPa, 144.45 GPa and 57.46 GPa, respectively. GGA + U formalism could successfully explain the semiconducting and ferrimagnetic behaviour of NiFe2O4. The spin-polarized electronic density of states reveals that the p - d hybridization between O and Fe atoms is responsible for the semiconducting nature of NiFe2O4. The ferrimagnetic behaviour of inverse spinel NiFe(2)O(4 )can be explained through the anti-parallel spin configuration of tetrahedrally and octahedrally occupied Fe atoms. The resultant magnetic moment is thus solely contributed by the octahedrally occupied Ni atoms. Spin-polarized band structure calculations reveal indirect band gap of 1.6 eV for spin-up channel and direct band gap of 2.2 eV for spin-down channel. (C) 2022 Elsevier B.V. All rights reserved.