title: Spin superstructure and noncoplanar ordering in metallic pyrochlore magnets with degenerate orbitals.
abstract: We study double-exchange models with itinerant t(2g) electrons in spinel and pyrochlore crystals. In both cases the localized spins form a network of corner-sharing tetrahedra. We show that the strong directional dependence of t(2g) orbitals leads to unusual Fermi surfaces that induce spin superstructures and noncoplanar orderings for a weak coupling between itinerant electrons and localized spins. Implications of our results to ZnV(2)O(4) and Cd(2)Os(2)O(7) are also discussed.
authors: Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors: Gia-Wei
authors: GW
authors: Chern
authors: Cristian D
authors: CD
authors: Batista