Magnetism in the actinides

Magnetism involving 5f electrons in the actinides exhibits a bewildering diversity that is difficult to fit within any conventional framework. In this article I review briefly some of the significant work that has been performed during the last 5 years. From itinerant 5f systems such as UFe2, to heavy-fermions exhibiting non-Fermi-liquid behaviour such as (U,Y)Pd-3, to quasi-localized materials such as NpBi, to fully localized compounds such as UPd3, the magnetism continues to provide both richness and surprises. Neutron scattering, especially inelastic scattering, provides the surest method to help define the "state of hybridization" in these compounds. Heavy-fermion superconductivity remains the most difficult aspect to understand. I argue that the communities working on both "conventional" actinides and heavy-fermion compounds would benefit from greater contact with each other.