Structure and physical properties of rare-earth zinc antimonides REZn1-xSb2 (RE = La, Ce, Pr, Nd, Sm, Gd, Tb)

摘要

The ternary rare-earth zinc antimonides REZn1-xSb2 (RE = La, Ce, Pr, Nd, Sm, Gd, Tb) were prepared by heating at 1050 degrees C followed by annealing at 600 degrees C. For all members, single-crystal X-ray diffraction studies indicated that the Zn deficiency is essentially fixed, corresponding to the formula REZn0.6Sb2, with no appreciable homogeneity range. These compounds adopt the HfCuSi2-type structure (Pearson symbol tP8, space group P4mm, Z = 2). Single-crystal electrical resistivity measurements confirmed the occurrence of an abrupt resistivity decrease near 4 K for RE = Ce, and a less pronounced one for RE= La, Pr, and Gd. Except for the ferromagnetic Cc (T-c = 2.5 K) and antiferromagnetic Tb (T-N = 10 K) members, all remaining compounds exhibit no long-range magnetic ordering down to 2 K, instead showing temperature-independent (RE = La), van Vleck (RE = Sm), or Curie-Weiss paramagnetism (RE = Pr, Nd, Gd). (c) 2006 Elsevier Inc. All rights reserved.