Intermediate valence in single crystals of (Lu_1−xY b_x)₃Rh₄Ge₁₃ (0 ≤ x ≤ 1)

Single crystals of (Lu1−x Y b x )3Rh4 Ge 13 were characterized by magnetization, specific heat, and electrical resistivity measurements. Doping Yb into the non-magnetic Lu3Rh4 Ge 13 compound tunes this cubic system’s properties from a superconductor with disordered metal normal state (x < 0.05) to a Kondo for 0.05 ≤ x ≤0.2 and intermediate valence at the highest Yb concentrations. The evidence for intermediate Yb valence comes from a broad maximum in the magnetic susceptibility and X-ray photoelectron spectroscopy. Furthermore, the resistivity displays a local maximum at finite temperatures at intermediate compositions x, followed by apparent metallic behavior closest to the Yb end compound in the series.