Neutron scattering study on 5f itinerant antiferromagnet UPdGa

Ikeda, Shugo; Metoki, Naoto   ; Haga, Yoshinori   ; Kaneko, Koji   ; Matsuda, Tatsuma; Onuki, Yoshichika

We have succeeded to grow a single crystal of uranium ternary intermetallic compound UPdGa by the Ga self-flux method. The magnetic susceptibility showed a weak temperature dependence and small anisotropy,consistent with an itinerant character of 5 electrons. We observed a clear drop in the susceptibility and electrical resistivity below the Neel temperature = 31 K. The magnetic structure was studied by means of a neutron diffraction measurement. We observed an antiferromagnetic peak with the propagation vector =[0,0,1/2]. The uranium 5 moment of 0.33 parallel to the -axis was found to order ferromagnetically in the basal -plane and coupled antiferromagnetically along the -axis.