Neutron scattering on the strongly correlated electron CeNi1-xCux system: from non-magnetic behaviour to long-range magnetic order

The ground state of the strongly correlated electron CeNi1-xCux compounds h as been investigated by means of neutron scattering experiments. Thus, magn etic diffraction was performed fur compounds showing long-range magnetic or der (x > 0.2). An evolution from a collinear ferromagnetic structure for x = 0.6 to a simple antiferromagnetic one for CeCu takes place through some m ore complex magnetic structures for intermediate compositions. The magnetic moments are continuously reduced when the Ni content increases reflecting the progressive enhancement of the Kondo screening. The large reduction fou nd for x = 0.6 compound is discussed and the existence of a spin glass like component of the magnetic moment cannot. be discarded. Front the quasielas tic spectra, we have obtained the Kondo temperatures which are close to the magnetic ordering ones. The quasielastic line-width evolves: from it linea r temperature dependence to a T-1/2 behaviour when approaching the non-magn etic limit. Then, this: system provides an interesting example for the evol ution of unstable 4f such relaxation regimes when modifying the hybridisati on strength.