Heavy-fermion-like excitations in metallic Nd2-yCeyCuO4.

The specific heat of Nd 2-y Ce y CuO 4 , 0≤y≤0.2, was measured between 35 mK and 10K. A Schottky anomaly in Nd 2 CuO 4 , due to exchange interactions between Nd and Cu moments, shifts upon Ce doping to lower temperatures. In the metallic state (y≥0.15), a linear term with coefficient y≃4 J/K 2 per mole Nd is found below 300 mK. For y=0.2, a constant value of the magnetic susceptibility in the same temperature range and changes of C p in applied magnetic fields suggest an interpretation in analogy to a heavy-fermion system resulting from the coupling between Nd moments and conduction electrons