Magnetic Properties of RE₃Pd₆Sb₅ (RE = Pr, Nd,Gd) and a Group-Subgroup Scheme for Ce₃Pd₆Sb₅ and Yb₅Cu₁₁Sn₈

Abstract

The Ce 3 Pd 6 Sb 5 -type antimonides RE 3 Pd 6 Sb 5 (RE = Pr, Nd, Sm, Gd, Tb) were synthesized by arc-melting and subsequent annealing in sealed silica ampoules in a high-frequency furnace. The new compounds Sm 3 Pd 6 Sb 5 (a = 1337.0(5), b = 441.5(1), c = 988.6(3) pm) and Tb 3 Pd 6 Sb 5 (a = 1328.8(4), b = 439.9(2), c = 976.6(5) pm) were characterized by powder X-ray diffraction data. The RE 3 Pd 6 Sb 5 antimonides adopt an ordered defect structure that derives from the CaBe 2 Ge 2 type. Their crystal chemistry is compared to the structures of Ce 8 Rh 17 Sb 14 and Yb 5 Cu 11 Sn 8 on the basis of group-subgroup schemes. Temperature-dependent magnetic susceptibility data of the samples with RE = Pr, Nd and Gd show Curie-Weiss paramagnetism of the trivalent rare earths. Low-field susceptibility measurements reveal magnetic ordering at low temperatures.