Abstract
Itinerant magnets with large orbital moments are uncommon. We show that UGa3 is such a material where the itinerant magnetism is carried by the 5f states. The definitive evidence comes from neutron diffraction measurements of the magnetization distribution, where a significant difference is observed in the momentum dependence of the scattering amplitude above and below TN. The change in the magnetization distribution when the antiferromagnetic order appears is due to the antiparallel coupling of large atomic 5f spin and orbital moments below TN, whereas above TN there is spin degeneracy and no disordered local moments.