First-principles investigations of Cr doping effects on electronic structure and magnetic properties in Sr 2FeReO 6

Abstract

The electronic structures and magnetic properties of double perovskites Sr 2Fe 1− x Cr x ReO 6 ( x = 0.0 , 0.25, 0.5, 0.75, 1.0) have been studied within the local spin density approximation (LSDA) and LSDA + U schemes. The calculated results reveal that with increasing Cr content the cell volume shrinks 2.61%; the Fe/Cr site magnetic moment decreases while the Re-site moment increases. The total spin magnetic moment linearly decreases with the Cr doping from 3.00 μ B for x = 0.00 down to 1.00 μ B for x = 1.00 per formula unit. The magnetic coupling constants increase with increasing x. The electronic structure calculations indicate that the electronic concentration in the Re spin-down subband slightly increases resulting from the increase of bonding–antibonding interaction between the localised and the delocalised states in spin-down band; the coupling of O- 2 p ↑ and transition-metal- 3 d ↑ is substantially enhanced with the Cr doping. We discuss the origin of the anomalously high T C of Cr-doped Sr 2FeReO 6 compounds in terms of band hybridization effects.