LONG-RANGE MAGNETIC ORDER ON THE KONDO-LATTICE - SDW IN CE(RU1-XRHX)(2)SI-2 AS STUDIED BY NEUTRON-DIFFRACTION

We report results of neutron-diffraction experiments which have been c arried out to study the long range magnetic order developing on the Ko ndo lattice of the pseudo-binary-alloy system Ce(Ru1-xRhx)(2)Si-2 with x around 0.15. The ground-state structure of the ordered phase has a sinusoidal modulation of the moment: that is, a modulation with an inc ommensurable wave number and a uniaxial polarization. We assign this p hase to the same category of magnetism as that of the spin-density wav e in metals, Several characteristic quantities of this ordering such a s the order parameter, the wave number, the amplitude and the anisotro py of the polarization and the anomaly in the lattice-constant are ana lyzed and discussed in terms of either the s-d model or the hybridized f-band model of Kondo effect.