Polarized neutron diffraction study of spin and orbital moments in UAsSe

Unpolarized and polarized neutron diffraction experiments have been perform ed on a single crystal of tetragonal UAsSe. The measured magnetic form fact or corresponds well to that theoretically predicted for a U4+ ion. The separation of contributions from the spin (mu(S)) and orbital (mu(L)) m oment yielded values of -0.65(9) and 2.07(5) mu(B), respectively, giving th e total magnetic moment of 1.42(4) mu(B) at the uranium site compared to th e 1.29(2) mu(B) per U atom obtained from magnetization measurements. The -m u(L)/mu(S) ratio equal to 3.2(4) indicates that the hybridization of 5f ele ctron states with conduction band states is rather weak.