Rare-earth metal gallium silicides via the gallium self-flux method. Synthesis, crystal structures, and magnetic properties of RE(Ga1−xSix)2 (RE=Y, La–Nd, Sm, Gd–Yb, Lu)

Fifteen ternary rare-earth metal gallium silicides have been synthesized using molten Ga as a molten flux. They have been structurally characterized by single-crystal and powder X-ray diffraction to form with three different structures—the early to mid-late rare-earth metals RE=La–Nd, Sm, Gd–Ho, Yb and Y form compounds with empirical formulae RE(GaxSi1−x)2 (0.38≤x≤0.63), which crystallize with the tetragonal α-ThSi2 structure type (space group I41/amd, No. 141; Pearson symbol tI12). The compounds of the late rare-earth crystallize with the orthorhombic α-GdSi2 structure type (space group Imma, No. 74; Pearson symbol oI12), with refined empirical formula REGaxSi2−x−y (RE=Ho, Er, Tm; 0.33≤x≤0.40, 0.10≤y≤0.18). LuGa0.32(1)Si1.43(1) crystallizes with the orthorhombic YbMn0.17Si1.83 structure type (space group Cmcm, No. 63; Pearson symbol oC24). Structural trends are reviewed and analyzed; the magnetic susceptibilities of the grown single-crystals are presented.

Graphical abstractThis article details the exploration of the RE–Ga–Si ternary system with the aim to systematically investigate the structural “boundaries” between the α-ThSi2 and α-GdSi2-type structures, and studies of the magnetic properties of the newly synthesized single-crystalline materials.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Light rare-earth gallium silicides crystallize in α-ThSi2 structure type. ► Heavy rare-earth gallium silicides crystallize in α-GdSi2 structure type. ► LuGaSi crystallizes in a defect variant of the YbMn0.17Si1.83 structure type.