Structural optimization stability, electronic, high performance thermoelectric, and magnetic characteristics of MgFe₂O₄ spinel for high-temperature energy conversion and spintronic applications via first principles investigation

This work uses density functional theory (DFT) in the FP-LAPW technique implemented in WIEN2k to offer comprehensive first-principles analysis of the structural, electronic, thermoelectric, and magnetic properties of MgFe2O₄. Phonon dispersion confirmed dynamical stability, and structural optimisation proved the cubic spinel phase with equilibrium lattice parameters and bulk modulus in agreement with experimental data. The accuracy of electronic band structure calculations using the TB-mBJ potential has improved over traditional GGA, revealing an indirect band gap of 3.1 eV. According to transport parameters studied using BoltzTraP; the Seebeck coefficient was high at moderate temperatures (600 K) and decreased at higher temperatures as a result of phonon-phonon and phonon-electron scattering and bipolar conduction. The thermoelectric figure of merit (ZT) showed promising efficiency, that is 1.31 at 1200 K. The ferrimagnetic ordering was confirmed by magnetic analysis with a net moment of 4.7 µB of GGA + U approach, highlighting MgFe2O₄ as a stable multifunctional material for spintronic and energy conversion applications.