EVIDENCE FOR ANISOTROPIC HYBRIDIZATION IN URANIUM-COMPOUNDS

We have performed polarized-neutron experiments on a single crystal of paramagnetic URuAl with the ZrNiAl hexagonal structure. Comparisons with the magnetization density previously determined for ferromagnetic URhAl show that in both materials there is a large (similar to 30% of the uranium signal) magnetic moment induced by hybridization between the 5f and 4d electrons at the 4d site. However, these effects are present only on the d sites in the (001) plane-an equally close d site out of the plane shows no such effects. These results show the importance of anisotropic 5f-ligand interactions.