Directional frustration of magnetic moments in (U0.50DY0.50)Ni2B2C

Polycrystalline (U0.50Dy0.50)Ni2B2C solid solution was prepared and found b y X-ray diffraction to crystallize in BCT LuNi2B2C-type structure (space gr oup I4/mmm) of the end compounds UNi2B2C and DyNi2B2C. AC susceptibility an d magnetization show paramagnetic behavior down to 6.5 K, with the values t heta = - 5(5)K and mu(eff) = 7.7(1) mu(B), compatible with those of the end compounds, and indicate possible cooperative phenomena at lower temperatur es. The observed paramagnetism, at variance with antiferromagnetic ordering in (Pr0.50Dy0.50)Ni2B2C, is attributed to a directional frustration of the magnetic moments on the (U,Dy) site. (C) 2000 Elsevier Science B.V. All ri ghts reserved.