4F-CONDUCTION ELECTRON HYBRIDIZATION IN TERNARY CE-TM-AL COMPOUNDS

We present an investigation of Ce-TM-Al phase diagrams with TM = Ru, Pd, Pt and Au. Several new compounds have been characterized by measurements of the electrical resistivity rho(T), the dc susceptibility chi(T) and, in some cases, the specific heat C(T). We find that in the compounds with TM=Ru, the hybridization strength between 4f and conduction electrons is strong, leading in most compounds to an intermediate valent (IV) state. By contrast, most of the investigated compounds with TM = Pd, Pt and Au order magnetically indicating a much weaker hybridization strength. However, some of the Pt and especially Pd compounds are very near to the crossover from the magnetic to the non-magnetic regime as deduced from a Kondo-type maximum in the resistivity and a large electronic specific heat at low temperatures.