paper

Preferential site ordering alters the magnetic structure of SmRuSnGe (-2)

arXiv:2507.13243 · doi:10.1021/acs.inorgchem.5c02985

Abstract

An important aspect of materials research is the ability to tune different physical properties through controlled alloying. The LnMX (Ln = Lanthanide, M = Transition Metal, X = Tetrel) filled skutterudite family is of interest due to the tunability of its constituent components and their effects on physical properties, such as superconductivity and complex magnetism. In this work, SmRuSnGe (x = 0 -- 2) was synthesized via excess Sn-flux and characterized using powder and single-crystal X-ray diffraction, magnetometry, X-ray photoelectron spectroscopy, and heat capacity. SmRuSn and its Ge-solid-solution members crystallize in the Pm-3n space group, which has two unique Wyckoff positions for the tetrel (X) site. In the solid solution members, Ge shows preferential occupancy for one of the two Wyckoff sites, reaching 60 and 100 occupancy when x = 1 and 2, respectively. Magnetometry and heat capacity measurements of SmRuSn indicated antiferromagnetic ordering at = 7.3 K. However, SmRuSnGe and SmRuSnGe showed notably lower-temperature antiferromagnetic phase transitions with substantial peak-broadening at = 5.5 K and 4.1 K, respectively. These data suggest that alloying Ge into SmRuSn causes magnetic frustration within the structure, likely attributable to a change in the density of states from additional Ge states at the Fermi level. This work demonstrates that preferentially alloying Ge in SmRuSnGe allows for more precise tunability of its magnetic structure, elucidating design principles for different quantum phases in intermetallic materials.

36 Pages, 12 Figures

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