Intermediate valence state of Ce in the novel quaternary compound CeRu2Sn2Zn18

A novel quaternary compound CeRu2Sn2Zn18 has been synthesized by a self-flux method. The structural, magnetic, and transport properties have been studied using single crystal X-ray structural analysis and measurements of the electrical resistivity ρ, specific heat C, and magnetic susceptibility χ. The X-ray structural analysis reveals that CeRu2Sn2Zn18 is an ordered variant of the CeCr2Al20- and ZrZn22-types, as found in the isostructural RT2Sn2Zn18 (R = La, Ce, Pr, Nd, T = Fe, Co, Ru). ρ shows no sign of a phase transition down to 2 K and is proportional to T2 below 50 K. χ exhibits a broad peak near 100 K, and the values are on the order of 10−3 emu/mol over a temperature range of 2–300 K. The electronic specific heat coefficient γ is found to be 69 mJ/K2 mol, which is approximately seven-fold larger than that of the La analog. These findings indicate that CeRu2Sn2Zn18 is in the intermediate valence state.