DEVELOPMENT OF MAGNETIC ORDER IN CECU2(SI1-XGEX)(2)

Measurements of specific heat (C-p), AC and DC susceptibility, and res istivity were carried out on samples of CeCu2(Si1-xGex)(2). The system evolves continuously from the heavy fermion state at x = 0 to an anti ferromagnetically (AF) ordered state at x = 1, although the magnetic s tructure undergoes significant modifications. The results strongly sug gest that the AF-ordering emerges from the A-phase of CeCu2Si2. Below the ordering temperature a systematic change in curvature in C-p(T) is observed for x greater than or equal to 0.6, that gets more pronounce d with decreasing x, and al x = 0.4 a sharp anomaly is observed sugges ting the existence of a critical point for 0.3 < x < 0.5. Below 1 K, a small anomaly is present al some concentrations. The results are comp ared with those on the Ce(Cu1-xNix)(2)Ge-2 system.