First-principles investigations of Cr doping effects on electronic structure and magnetic properties in Sr2FeReO6

The electronic structures and magnetic properties of double perovskites Sr2Fe1−xCrxReO6 (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 3.00μB for x=0.00 down to 1.00μB 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-2p↑ and transition-metal-3d↑ is substantially enhanced with the Cr doping. We discuss the origin of the anomalously high TC of Cr-doped Sr2FeReO6 compounds in terms of band hybridization effects.