Study of the Ce(Rh1−xPdx)2Si2 alloy: evidence for itinerant character of the magnetic order in CeRh2Si2

We present electrical resistivity (ρ(T )) and specific heat (Cel(T )) measurements of alloys on the Rh rich side of the phase diagram of the Ce(Rh1−xPdx)2Si2 system and compare the results with those obtained at intermediate and low Rh concentrations. The analysis of the x-evolution of the entropy and the scaling behaviour of Cel(T ) and ρ(T ) clearly confirm a separation of the magnetic phase diagram into two regions. The region x ≤ 0.3, showing a concentration independent characteristic temperature To ≈ 45K, while for x > 0.3 To decreases down to To(x = 1) ≈ 15K. This characteristic temperature is obtained by scaling the Cel(T, x > 0.3) results as a function of the reduced temperature T/To. At low Pd-content, the antiferromagnetic ordering temperature TN decreases very rapidly from TN = 36K in pure CeRh2Si2 to TN = 18K at x = 0.1. With higher Pd concentration it stabilized at TN ≈ 15K whereas the magnitude of the anomalies in Cel(T ) and in the susceptibility around TN are further reduced and disappear at x ≈ 0.3. This is in contrast to the behavior found on the Pd-rich side, where TN decreases continuously to zero with increasing Rh content. The pronounced differences observed between both phase boundaries and the drastic effect of doping on the Rh rich side suggest an itinerant character in CeRh2Si2, in contrast to the localized character of CePd2Si2. A further evidence for the itinerant character in CeRh2Si2 is given by the ρ(T ) dependence observed for x ≤ 0.3, which scales with ρ(T ) of the prototype itinerant compound YCo2. The exponent (n) of the power law observed in ρ(T ) at low T presents a broad minimum with n ≈ 1.2 in the intermediate concentration range 0.4 ≤ x ≤ 0.6, which we attribute to the effect of the random atomic distribution of Rh and Pd in this region. PACS. 71.10Hf Non-Fermi-liquid ground states, electron phase diagrams and phase transition in model systems – 71.27.+a Strongly correlated electron systems; heavy fermions 2 M. Gómez Berisso et al.: Study of the Ce(Rh1−xPdx)2Si2 alloy