Study of Half Metallic Ferromagnetism and Thermoelectric Properties of the Spinels MgCo2(S/Se)4 for Spintronic and Energy Harvesting

Half metallic ferromagnetism has gained immense importance due to its advanced applications in spintronic. This article comprehensively elaborates on the magnetic and thermoelectric characteristics of the spinels MgCo₂(S/Se)₄ by the DFT approach. The optimized energies in ferromagnetic (FM) and antiferromagnetic (AFM) states confirm the stability of FM states, which is further elucidated thermodynamically by formation energy. The Heisenberg model is engaged to report the Curie temperature (Tc). The band structures and DOS are resolved to confirm half-metallic ferromagnetism and spin polarization. Furthermore, the exchange energies, crystal field energy, and exchange constants are computed to address the nature of ferromagnetism. The shifting of a magnetic moment from Co to nonmagnetic sites shows that the exchange of electrons is responsible for ferromagnetism. Moreover, the transport characteristics of the studied spinel are addressed by the Seebeck coefficient, electrical conductivity, power factor, and thermal conductivity in the temperature range from 0 to 800 K.