Magnetic structure of the Kondo compound UCu5In

The crystal and magnetic structures of UCu5In have been investigated by means of neutron powder diffraction measurements. This compound crystallizes with the orthorhombic CeCu5Au-type structure (space group Pnma). Below 25(1) K, UCu5In exhibits a non-collinear antiferromagnetic structure of uranium magnetic moments, which are confined to the ac plane. At 1.4 K the ordered moment amounts to 1.55(2)μB and is tilted from the c-axis by an angle of 58.2(5)°. This angle is slightly temperature-dependent and increases with rising temperature. This rather complex magnetic structure of UCu5In probably results from the interplay of anisotropic magnetic exchange interactions and a strong crystal electric field effect.