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We report a resonant x-ray-scattering determination of order parameter of the Nd sublattice in the quasione-dimensional antiferromagnet, Nd 2 BaNiO 5 . We find that long-range order develops below T N ϭ48 K, and that the staggered magnetization continues to grow down to Tϭ10 K. This is in contrast with the behavior of the Ni sublattice, which quickly saturates, as determined previously by neutron-scattering. We find this behavior is modeled well by a self-consistent mean-field theory. Large resonant enhancements were obtained at both the Nd L II and L III absorption edges, with the largest count rates being achieved at the L II edge, where structure consistent with magnetic diffraction anomalous fine structure was observed. A double peak observed at the L III resonance is also discussed. ͓S0163-1829͑96͒06234-0͔

We use synchrotron x-ray scattering from LaL&SrQ.2Ni04 and LaL925SrQQ75Cu04 to establish a direct relationship between carriers due to Sr doping and strong dift'use scattering. In the nickelate the scattering is peaked at the fourfold symmetric satellite positions (~b, + B,l), where the basal-plane coordinate 8 varies with the out-of-plane coordinate l of the momentum transfer. A similar scattering pattern is observed in the cuprate, but with smaller values for 8.