Structure and magnetic properties of RE2CuIn3 (RE=Ce, Pr, Nd, Sm and Gd)

The ternary copper indides RE2CuIn3≡RECu0.5In1.5 (RE=Ce, Pr, Nd, Sm and Gd) were synthesized from the elements in sealed tantalum tubes in an induction furnace. They crystallize with the CaIn2-type structure, space group P63/mmc, with a statistical occupancy of copper and indium on the tetrahedral substructure. These indides show homogeneity ranges RECuxIn2−x. Single crystal structure refinements were performed for five crystals: CeCu0.66In1.34 (a=479.90(7) pm, c=768.12(15) pm), PrCu0.52In1.48 (a=480.23(7) pm, c=759.23(15) pm), NdCu0.53In1.47 (a=477.51(7) pm, c=756.37(15) pm), SmCu0.46In1.54 (a=475.31(7) pm, c=744.77(15) pm), and GdCu0.33In1.67 (a=474.19(7), c=737.67(15) pm). Temperature-dependent susceptibility measurements show antiferromagnetic ordering at TN=4.7 K for Pr2CuIn3 and Nd2CuIn3 and 15 K for Sm2CuIn3. Fitting of the susceptibility data of the samarium compound revealed an energy gap ΔE=39.7(7) K between the ground and the first excited levels.