Structure and magnetic properties of RE2Cu2Cd

The ternary intermetallic compounds RE2Cu2Cd (RE=Y, Sm, Gd–Tm, Lu) were synthesized by induction-melting of the elements in sealed tantalum tubes. The samples were characterized by X-ray powder diffraction. The structure of Gd2Cu2Cd was refined from single crystal X-ray diffractometer data: Mo2FeB2 type, space group P4/mbm, a=756.2(3), c=380.2(3) pm, wR2=0.0455, 321 F2 values, 12 variables. The structures are 1:1 intergrowth variants of slightly distorted CsCl and AlB2 related slabs of compositions RECd and RECu2. The copper and cadmium atoms build up two-dimensional [Cu2Cd] networks (257 pm Cu–Cu and 301 pm Cu–Cd in Gd2Cu2Cd) which are bonded to the rare earth atoms via short RE–Cu contacts (290 pm in Gd2Cu2Cd). Temperature dependent susceptibility measurements of RE2Cu2Cd with RE=Gd, Tb, Dy, and Tm show experimental magnetic moments which are close to the free RE3+ ion values. The four compounds show ferromagnetic ordering at TC=116.7(2), 86.2(3), 48.4(1), and 14.5(1) K, respectively, as confirmed by heat capacity measurements. Dy2Cu2Cd shows a spin reorientation at TN=16.9(1) K.