NEUTRON-SCATTERING STUDIES OF MAGNETIC-PROPERTIES OF ACTINIDE SYSTEMS

In this article we review neutron scattering studies of the magnetic properties of actinide systems over the last 15 years, with particular emphasis on the work since 1984 and the reviews by Rossat-Mignod et al. and Buyers and Holden. In section 2 the results obtained on the actinide dioxides UO2, NpO2 and PuO2 at spallation sources and the recent observation of intermultiplet transitions in UPd3 and UPt3 are presented. In section 3 a discussion is given of magnetization densities, starting with the almost localized system such as PuSb and continuing to more recent work on itinerant intermetallic systems such as UNi2, UFe2 and PuFe2. In these latter systems the ratio mu(L)/mu(S) of the orbital and spin moments may be determined by neutrons and compared to theory. In section 4 we present work on compounds with the NaCl crystal structure. This includes complex magnetic phase diagrams, as found for example in UAs and NpAs, the discussion of the results of critical scattering experiments, and neutron inelastic experiments on ferromagnets such as PuSb and UTe. In section 5 the work on single crystals of U-containing heavy fermions is presented. In these systems neutron scattering has been able to characterize the small magnetic moments and the nature of the magnetic correlations, which are frequency dependent. A summary of the significant progress and problems remaining is given in section 6.