Electronic structure and thermodynamic properties of Ce₃Rh₄Sn₁₃and La₃Rh₄Sn₁₃

Abstract

The electronic structure and thermodynamic properties of CeRh2Sn4 and LaRh2Sn4 are reported. The crystal structure of CeRh2Sn4 has been determined from single-crystal diffraction experiments. The Ce core-level x-ray photoemission spectra and Ce LIII x-ray absorption data unanimously indicate a stable trivalent state of the Ce ions in CeRh2Sn4, consistent with static magnetic susceptibility. Thermodynamic measurements for CeRh2Sn4 show a noncollinear antiferromagnetic ordering with a ferromagnetic component at TN ≈ 3.2 K. There is evidence for spin fluctuations in both CeRh2Sn4 and LaRh2Sn4. A Fermi surface analysis reveals sections, which could generate ‘nesting ’ instabilities and be responsible for the spin fluctuation effects. Both CeRh2Sn4 and LaRh2Sn4 exhibit slight homogeneity ranges and can be described by RE1+x Rh2Sn4−x, where 0 x 0.2 for Ce and 0 x 0.1 in the case of La. Implantation of additional Ce atoms into the CeRh2Sn4 structure leads to a distinct lowering of TN and the weakening of the ferromagnetic component of the magnetic ground state, whereas for the La-based systems the alloying reduces the strong diamagnetism. (Some figures in this article are in colour only in the electronic version) 1.