Yb- and Ce- based, dilute rare earth intermetallic compounds: Fully ordered compounds that approach the single Kondo-impurity limit

Dilute, rare earth intermetallic compounds are ordered structures in which the rare earth comprises less than $5\%$ atomic of the compound, but still fully occupies a unique crystallographic site. Whereas for local moment bearing R-members these series offer the possibility of studying the RKKY interaction for relatively large R – R spacing, the R = Yb and Ce members offer a unique opportunity to study the Kondo lattice for concentrations that start to approach the single ion limit. In this talk we will present data on six Yb-based, and two Ce-based, dilute rare earth intermetallic compounds. Despite the rather different behavior of the analogous Gd-based members, the thermodynamic and transport properties of the Yb-based materials are rather similar. This new family of heavy Fermion materials promises to be a fruitful testing ground for current theories of correlated electron physics.