Magnetic Properties of NiFe2O4 Compound: Ab Initio Calculation and Monte Carlo Simulation

The structural, electronic, and magnetic properties of the NiFe2O4 compound are studied using several theoretical methods such as first-principle calculations based on density functional theory (DFT), Monte Carlo simulations, and mean-field theory. The exchange-correlation potential was resolved by generalized gradient approximation (GGA) that underestimates the band gap energy value; therefore, this later needed to be corrected using the GGA + U approximation. The gap energy value (1.10 eV) obtained by the theoretical method is in good agreement with experimental value (0.99 eV). Using ab initio calculations, the exchange-coupling interactions are J(1) = 40.665 meV, J(2) = 45.382 meV, and J(3) = -3.260 meV. Moreover, the semiconductor NiFe2O4 compound exhibits a second-order ferromagnetic-paramagnetic phase transition around T-C = 844 K; this value is in good agreement with experimental results. The total magnetization, susceptibility, and specific heat of this compound are investigated.