Uranium does not form binary compounds with Fe and Co having the 2-17 stoichiometry, however, the hexagonal Th2Ni17-type crystal structure, which is characteristic for R2T17 with heavy rare-earth metals, can be stabilized by substitution of a small amount of third element, e.g. Si, for the T metal. In U2(T,Si)17 compounds, where a strong 5f-3d electron hybridization causing a delocalization of the 5f electrons is expected, the magnetic ordering of the U sublattice seems to be hardly possible. However, the single-crystal study of magnetic anisotropy U2(T,Si)17 compounds together with isostructural compounds of non-magnetic Lu gives arguments pointing to the magnetic contribution from the U sublattice. Results of magnetization studies of single crystals of U2(Fe1-xCox)13.6Si3.4 and U2Co17-xSix are discussed.
Magnetic behavior of uranium in strong ferromagnetic matrix of 3d-metals
Alexander V. Andreev
Institute of Physics of Academy of Sciences, Prague, Czech Republic
Institute for Materials Research, Tohoku University, Sendai, Japan