Magnetic properties of the AnFe2 compounds (An = U,Np, Pu,and Am)

The magnetic properties of the actinide Laves compounds (cubic C-15 crystal structure) with iron have been studied by magnetization, neutron diffraction, and Mössbauer-effect techniques. All the compounds exhibit a spontaneous magnetization. Magnetic moments of 0.06, 1.09, 0.45, and −0.4 μ_B are associated with the U, Np, Pu, and Am ions, respectively. The corresponding iron moments are 0.6, 1.4, 1.5, and 1.7 μ_B. The ferrimagnetic nature of AmFe₂ suggests a partial occupancy of the Am²⁺ :f⁷ state, inasmuch as the Am³⁺ :f⁶ state has a nonmagnetic ground state.