Study of Ce(Rh1-xPdx)2Si2:: pronounced differences between the CeRh2Si2 and CePd2Si2 ground states

We present electrical resistivity and specific heat measurements of alloys on the Rh rich side of the phase diagram of the Ce(Rh1-xPdx)(2)Si-2 system. We compare these results with those obtained at intermediate and low Rh concentrations. The analysis of the concentration and temperature dependence of the entropy and of the scaling behaviour of C-et(T) and rho(T) clearly confirm a separation of the magnetic phase diagram into two regions: the region x less than or equal to 0.3, showing a concentration independent characteristic temperature for the 4f-electrons with T-0 approximate to 45 K, while for x > 0.3, T-0 decreases to T-0(x = 1) approximate to 15 K. At low Pd-content, T-N decreases very rapidly from T-N = 36 K in pure CeRh2Si2 to T-N = 18 K at x = 0.1. With higher Pd concentration T-N stabilizes at T-N approximate to 15 K whereas the magnitude of the anomalies in C-et(T) and in the susceptibility around T-N are further reduced and disappear at x approximate to 0.3. This differs from the behavior found on the Pd-rich side, where T-N 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 CeRh2 Si-2, in contrast with the localized character of CePd2Si2. Further evidence for the itinerant character of CeRh2Si2 is given by the rho(T) dependence observed for x less than or equal to 0.3, which scales with rho(T) of the prototype itinerant compound YCo2.