Tuning the magnetic ground state of Ce1−xYbxRhIn5 by Yb valence fluctuations

We characterize the properties of Ce1−xYbxRhIn5 single crystals with 0≤x≤1 using measurements of powder x-ray diffraction, energy dispersive x-ray spectroscopy, electrical resistivity, magnetic susceptibility, specific heat, x-ray absorption near edge structure (XANES), and neutron diffraction. The Yb valence vYb, calculated from the magnetic susceptibility and measured using XANES, decreases from 3+ at x=0 to ∼2.1+ at xact=0.2, where xact is the measured Yb concentration. A transition from incommensurate to commensurate antiferromagnetism is observed in neutron diffraction measurements along Q=(0.5,0.5,l) between 0.2≤xact≤0.27; this narrative is supported by specific-heat measurements in which a second robust feature appears at a temperature TI(TI