Investigating the Multifunctional Role of Sr2FeMnO6 Double Perovskite in Spintronic and Thermoelectric Properties

Herein, the double‐perovskite Sr 2 FeMnO 6 is investigated using density functional theory to investigate its electronic, magnetic, thermoelectric, and thermodynamic properties. The Sr 2 FeMnO 6 show the ferromagnetic phase stability with the formation energy of about −2.53 eV. Spin‐polarized band structure and density of states (DOS) calculations, performed using the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE‐GGA) and modified Becke–Johnson (GGA + mBJ) methods, confirm a half‐metallic nature. The system exhibits metallic behavior in the spin‐up channel, whereas the low‐spin counterpart demonstrates semiconducting characteristics with a bandgap of about 1.38 eV. A total magnetic moment of 7 μ B per formula unit is observed, predominantly originating from Fe and Mn atoms, with induced magnetism in oxygen attributed to Mn‐3 d , Fe‐3 d , and O‐2 p orbital interactions. The thermoelectric behavior of the system is studied by employing the semiclassical Boltzmann theory‐based BoltzTraP code for both spin channels, revealing zT values of 0.98 and 0.94 for spin‐down and spin‐up channels, respectively, with zT decreasing and the power factor increasing with temperature. These findings highlight Sr 2 FeMnO 6 as a promising candidate for spintronics, spin dynamics, and energy‐harvesting applications, offering insights into its multifunctional potential.