Neutron Diffraction Study of the Kondo Systems Ce6Ni1.67Si3 and Ce5Ni1.85Si3

Abstract

Neutron powder diffraction experiments were performed on the moderate Kondo systems Ce6Ni1.67Si3 and Ce5Ni1.85Si3. These measurements have shown that Ce6Ni1.67Si3 does not present a long range magnetic order down to 1.6 K, but only short range ferromagnetic correlations. Ce5Ni1.85Si3 undergoes an antiferromagnetic transition at TN ≈ 6 K. Its magnetic structure at 1.5 K and zero field is collinear with the magnetic moments along the hexagonal axis and can be described with the propagation vector k = (1/2 0 0). This antiferromagnetic order coexists with a short range ferromagnetic component.