Realization of half-metal antiferromagnetic (HM-AFM) behaviour in double perovskite Sr2CrReO6 on substitution of Tc at Cr site: Promising material for optoelectronics and thermoelectric applications via DFT framework

Abstract

• We have studied Sr 2 AReO 6 (A=Cr, Tc) by using both PBEsol-GGA and PBEsol+U. • We report ferrimagnetic half-metal in Sr 2 CrReO 6 while Sr 2 TcReO 6 shows antiferromagnetic half-metal (AFM-HM) behavior. • Among the two materials Sr 2 TcReO 6 is a promising material for spintronic application due to low loss of energy. • Also double perovskite Sr 2 TcReO 6 (STRO) shows high absorption coefficient at UV-Vis range of photon energy. Using the application of the first principle within the Full Potential Linearized Augmented Plane wave (FP-LAPW) method, the electronic, magnetic, optical and thermoelectric properties of double perovskite oxides Sr 2 AReO 6 (A=Cr, Tc)were systematically investigated. We have used the most appropriate functionals like PBEsol-GGA and PBEsol+U. The replacement of Cr atom by Tc atom in Sr 2 CrReO 6 leads to the transition of the magnetic configuration from ferrimagnet to complete antiferromagnet half-metal (AFM-HM) with zero magnetic moments. The mechanisms that govern the ferrimagnetism/antiferromagnetism in the two double perovskites are the Zener double exchange and hybridization p-d, respectively. A careful analysis of the optical and thermoelectric properties in this study leads to the conclusion that the antiferromagnet double perovskite Sr 2 TcReO 6 (STRO)has the power to convert the maximum amount of sunlight in the visible range compared to the ferromagnet compound Sr 2 CrReO 6 (SCRO). Further, we have obtained an optimal figure of merit (ZT∼1) and high electrical conductivity. Finally, the half-metallic antiferromagnetic double perovskiteSTRO is a potential energy material for the spintronic device, photovoltaic solar cells and thermoelectric applications.