Evidence of short range magnetic order at four times Tc in a metallic compound containing Fe: Susceptibility and paramagnetic scattering in CeFe2

Abstract

Below 230 K CeFe2 orders with a saturation magnetic moment of 1.15 μB/Fe at 4.2 K. The paramagnetic effective moment deduced from the Curie-Weiss law is 3.7 μB. Reported here are the results of neutron paramagnetic scattering measurements obtained between 300 K and 870 K on CeFe2. The technique of polarization analysis has been used to obtain a unique measurement of the magnetic cross-section. The Fe moment determined in this way is about 1 μB, close to that observed in the ferromagnetic state. However, strong ferromagnetic correlations are found to persist up to the highest temperature used in this study, i.e., 870 K. The results are in complete agreement with recent theories which tend to reconcile 3d band magnetism with the persistence of a moment in the paramagnetic state. In conclusion, effective moments derived from susceptibility measurements do not allow an understanding of the 3d magnetism in the paramagnetic state.