Abstract:
The electronic structures and magnetic properties of the double perovskite Sr2CoReO6 have been studied using the first-principles method based on the density function theory (DFT) with the projector augmented wave (PAW) potentials of the generalized gradient approximation. The calculated results show that the magnetic moments of Co2+ and Re5+ are 2.425 μB and -0.488 μB respectively,thus antiferromagnetic coupling is constructed via oxygen between them. Both occupied and unoccupied s and three p states of Co2+ ion are located far from the Fermi level, while all up-spin states and most down-spin states are completely filled for the s and three p states of Re5+ ion. The presence of the cubic symmetry of the octahedral coordination of the oxygen atoms around Co/Re site results in a splitting of the five-fold degenerate d states of a free Co/Re atom into triply degenerate t2g (dxy, dyz and dzx) states with lower energy and doubly degenerate eg (dz2 and dx2-y2) states with higher energy for either up-spin or down-spin. There are no direct interactions between two nearest Co—Co or Re—Re pairs, whereas along each Co—O—Re—O—Co or Re—O—Co—O—Re chains, the existence of hybridizations between Co 3d and 4s, O 2s and 2p, as well as Re 5p, 5d and 6s orbitals are confirmed.
