Spin and orbital ordering of Nd1-xSrxMnO3 from LSDA+U calculations

The electronic structures of Nd1-xSrxMnO3 with x = 9/16 were studied by usi ng the rotation-invariant local spin density approximation (LSDA)+U formali sm in the framework of the linear-muffin-tin orbital method in the atomic s phere approximation. The experimental magnetic structure is calculated to b e the energetically lowest one among the different possible spin configurat ions for every compound under consideration. The orbital ordering is clearl y demonstrated by the partial Mn 3d densities of stares projected into a na tural local basis for every MnO6 octahedron. The mechanism of antiferromagn etic and ferromagnetic couplings in these materials is discussed. Antiferro magnetic interlayer coupling at x=9/16 is attributed to a crystal structure with an anisotropic shorter interlayer distance. [S0163-1829(99)00815-2].