Directional frustration of magnetic moments in (U0.50Dy0.50)Ni2B2C

Abstract Polycrystalline (U 0.50 Dy 0.50 )Ni 2 B 2 C solid solution was prepared and found by X-ray diffraction to crystallize in BCT LuNi 2 B 2 C-type structure (space group I4/mmm) of the end compounds UNi 2 B 2 C and DyNi 2 B 2 C. AC susceptibility and magnetization show paramagnetic behavior down to 6.5 K, with the values θ =−5(5) K and μ eff =7.7(1) μ B , compatible with those of the end compounds, and indicate possible cooperative phenomena at lower temperatures. The observed paramagnetism, at variance with antiferromagnetic ordering in (Pr 0.50 Dy 0.50 )Ni 2 B 2 C, is attributed to a directional frustration of the magnetic moments on the (U,Dy) site.