Study of ferromagnetism and thermoelectric behaviour of thiospinels MgFe₂(S/Se)₄ for spintronics and energy harvesting

Magnesium-based spinel chalcogenides are remarkable materials for spintronic and energy harvesting applications. Therefore, the electronic, ferromagnetism, and thermoelectric characteristics of MgFe₂(S/Se)₄ spinels are addressed comprehensively by modified Becke Johnson potential (TB-mBJ). The stability of cubic phase has been illustrated by formation energy and energy released during optimization. The Curie temperature and spin polarization have been calculated by Heisenberg model and density of states at Fermi level. Ferromagnetism has been studied by exchange energies, double exchange mechanism, exchange constants, and hybridization process. The reduction of magnetic moment of Fe and its shifting on nonmagnetic (Mg, S/Se) sites shows the ferromagnetism is due to the exchange of electrons spin rather than the clustering effect of internal magnetic of Fe atoms in the structure. Moreover, thermoelectric analysis of studied spinels has been illustrated by electrical and thermal conductivities, Seebeck coefficient (S), and power factor.