We studied the proximity effect in order to probe the response of the heavy-fermion metal CeCu₆ to induced superconductivity. High-quality CeCu₆ films were grown by sputter deposition. Resistivity measurements show that the correlated electron state is formed. Bilayers were prepared of CeCu₆(75 nm)/Nb(d_Nb), with the Nb thickness d_Nb between 10 nm and 50 nm. Measured were the superconducting transition temperature T_c and the parallel critical fields H_c2^||. We find that the interface transparency is high, indicating that Fermi-velocity mismatch effects are not significant, but the coherence length of the induced superconductivity is small, which is probably due to the very low Fermi-velocity in the heavy fermion metal.

PACS numbers: 71.27.+a, 74.50.+r