Soft x-ray resonant scattering at the Ni L 2,3 edges is used to test models of magnetic-and orbital-ordering below the metal-insulator transition in NdNiO 3 . The large branching ratio of the L 3 to L 2 intensities of the (1/2 0 1/2) reflection and the observed azimuthal angle and polarization dependence originates form a non-collinear magnetic structure. The absence of an orbital signal and the non-collinear magnetic structure show that the nickelates are materials for which orbital ordering is absent at the metal-insulator transition.

X-ray resonant magnetic scattering experiments using linear and circular polarized light were performed at the Ni Lz3 absorption edges on a Ag/Ni multilayer.A superlattice magnetic peak, due to the antiferromagnetic coupling between Ni layers, is evidenced. In the case of a ferromagnetic coupling, large changes in the charge peak (up to 15%) are observed upon reversal of the direction of the magnetic field. The magnetic scattering amplitude is evaluated to SI. O per nickel atom. Sum rules have been applied for the first time to the energy-dependent magnetic amplitude.