Neutron-diffraction study of antiferromagnetic order in U(Pt,Pd)(3)

Neutron-diffraction experiments have been carried out on single-crystalline samples of the heavy-fermion pseudobinaries U(Pt1-xPdx)(3) (x less than or equal to 0.05) in order to investigate the evolution of magnetic order. At low Pd contents (x = 0.002 and 0.005), small-moment magnetic order is observed below similar to 6 K,just like in pure UPt3. For x = 0.02 and 0.05, the ordered moment is about one order of magnitude larger compared to UPt3. The compound with x = 0.01 represents a most intriguing intermediate case as it exhibits a cross-over behaviour from small-moment to large-moment antiferromagnetic order.