Crystal chemistry and magnetic properties of the solid solutions Ca14−xRExMnBi11 (RE = La–Nd, Sm, and Gd–Ho; x ≈ 0.6–0.8)

Abstract

The new solid solutions Ca_14−xRE_xMnBi₁₁ (RE = La–Nd, Sm, and Gd–Ho; x ≈ 0.6–0.8) were prepared by using a Pb-flux technique and structurally characterized by single-crystal X-ray diffraction. All synthesized materials crystallize in the tetragonal Ca₁₄AlSb₁₁ structure type (space group: I4₁/acd, Pearson index: tI208). The magnetic responses of all the members of the series were investigated, and for all REs in this study, except for Sm, a ferromagnetic ordering was observed at T_C = 35–44 K. The Sm-containing sample shows a ferromagnetic-like transition at 40 K and enters a long-range antiferromagnetic state below 17 K. The magnetic behavior of Ca_14−xRE_xMnBi₁₁ differs from that of the isostructural Ca_14−xRE_xMnSb₁₁ series, emphasizing the importance of the weak magnetic interactions in complex crystal structures.