Synthesis and properties of LnRu2P2 (Ln = lanthanides) crystals

Crystals of ternary LnRu2P2 (Ln = Pr, Nd, Sm, Tb, Dy, Er) systems were synthesized, and their crystallographic, magnetic, and electric properties were investigated. All the crystals have a tetragonal ThCr2Si2-type structure of space group I4/mmm. The lattice constants decrease as the number of 4f electrons increases, reflecting the lanthanide contraction. An antiferromagnetic transition was observed for LnRu2P2 (Ln = Pr, Nd, Sm, Tb, Dy) at 25 K (Pr), 19 K (Nd), 15 K (Sm), 22.5 K (Tb), and 13 K (Dy). However, no transition was observed for ErRu2P2 down to 5 K. The Peff agrees well with the theoretical moment gJ(J+1) of lanthanides, suggesting that lanthanides make a major contribution to the magnetic moment of LnRu2P2. A spin-flop-like transition was observed in the M(H) curves of PrRu2P2 and TbRu2P2 at 4 and 8 kOe, respectively; however, no saturation was observed up to 55 kOe.