Dilution and non-Fermi-liquid effects in the CePtIn Kondo lattice

Abstract

Measurements of electrical resistivity(ρ(T)), magnetoresistivity (MR), magnetic susceptibility(χ(T)) and heatcapacity (CP(T)) arepresented for the (Ce1−xLax)PtIn alloy system of which the CePtIn parent is a known dense Kondocompound that does not order magnetically down to 50 mK.χ(T) for alloys0≤x≤0.8 exhibits Curie–Weissbehaviour. ρ(T) results indicate a transition from a dense Kondo behaviour for0≤x≤0.2 to a single-ion Kondoregion (0.3≤x≤0.8). The Kondoenergy scale as given by TK values calculated from MR studies and by the temperatureTmaxρ(mag) where the magneticcontribution to ρ(T) exhibits a maximum value, is compared with theoretical models. It is shown that theexperimental results not only depend on a volume effect as given by the compressibleKondo lattice model of Lavagna but in addition confirm the more complex behaviourrecently presented by Burdin and Fulde for a Kondo alloy system in which the magnetic(Ce) and non-magnetic (La) atoms are distributed randomly. Non-Fermi-liquidbehaviour is predicted by Burdin and Fulde at certain critical concentrationsof the alloy system and experimental evidence for this is presented throughχ(T),ρ(T) and CP(T) measurements.