Near compensated half-metal in Sr2NiOsO6.

The electronic and magnetic properties of tetragonal double perovskite Sr(2)NiOsO(6) were studied by use of the density functional theory and including the spin-orbit coupling. Compensated half-metal is found if the spin-orbit coupling is not considered. Spin-orbit coupling induces orbital moments on both Ni and Os, making Sr(2)NiOsO(6) a near compensated half-metal. Ferromagnetic phase is slightly favored over antiferromagnetic phase (by 4 meV). The small energy difference also suggests that both phases are competitive for the ground state. At ferromagnetic phase, the calculated net magnetic moment is 3.53 micro(B), in good agreement with experimental value of 3.44 micro(B). At antiferromagnetic phase, the net magnetic moment is 0.69 micro(B), in which the contribution from the net spin moment is 0.09 micro(B).