Impact of terbium (Tb) on ferromagnetism and thermoelectric behaviour of spinels MgTb₂(S/Se)₄ for spintronic

The ferromagnetism due to rare earth elements-based spinel chalcogenides has become emerging aspirant for spintronic devices. Therefore, theoretically computed electronic properties of MgTb2(S/Se)4 spinels are analyzed to comprehend the structural, magnetic, and thermoelectric characteristics. Thermodynamic stability is elucidated using the computed enthalpy of formation (Delta H), phonons dispersion band structures. Using structural optimizations, difference in the energy states has revealed the ferromagnetic (FM) state stability. The computed band structures (BS) and density of states (DOS) both depict a half-metallic ferromagnetic state exhibiting a net spin polarization at the Fermi energy level. The underlying ferromagnetic state has been suggested due to carrier mediated indirect RKKY exchange mechanism. The thermoelectric properties are calculated to evaluate their potential for wasted-heat to useful-electricity conversion applications. The small thermal conductivity, and highpower factor exhibited by MgTb2S4 at room temperature suggest it significant for applications in thermoelectric generators.