Breakup of heavy fermions on the brink of "phase A" in CeCu2Si2

We report resistivity, p(T), and specific-heat, C(T), results on near stoichiometric CeCu2Si2 samples, in the vicinity of a quantum critical point (QCP). The latter is defined by T-A --> 0, where T-A less than or similar to 0.8 K marks the transition into a spin-density-wave-type "phase A" which competes with heavy-fermion superconductivity below T-c approximate to 0.65 K. Upon approaching the QCP, p(T) and C(T) behave very disparately, suggesting a breakup of the heavy quasiparticles. Very surprising observations are being made for samples with T-A > 0 also.