Antiferromagnetic ordering between unstable 4f shells in CeAl₂

We review the experimental situation of the unusual compound CeAl2 based on inelastic neutron scattering and specific heat measurements. The most interesting aspect of CeAl2 is its low temperature behavior. Below 3.9 K, a complicated antiferromagnetic structure coexists with a dynamic interaction between Ce moments and conduction electrons. It is argued that this dynamic interaction is due to the Kondo effect rather than to valence fluctuations. The experimental situation can be phenomenologically well described with the aid of a local model