We have examined the ground-state properties of the putative intermediate valency and/or charge density wave (CDW) system ${\mathrm{Yb}}_5{\mathrm{Ir}}_4{\mathrm{Si}}_{10}$ via resistivity, specific heat, magnetic susceptibility, and x-ray absorption spectroscopy. The bulk properties confirm a CDW-type anomaly at $48\mathrm{K}$, but show that all the Yb ions are in an integral trivalent $4f^{13}$ state. Additionally, our low-temperature measurements reveal two magnetic transitions at 2.3 and $1.1\mathrm{K}$, respectively. The compound shows Kondo-lattice-type behavior that might be responsible for the weak-coupling nature of the CDW evidenced by the specific heat data.

• Received 19 October 2004

DOI:https://doi.org/10.1103/PhysRevB.71.060406