A recently predicted inelastic charge-imbalance relaxation process associated with the proximity of a normal metal to a superconductor is confirmed through measurements of the low-voltage dc resistance of superconductor—insulator—normal-metal tunnel junctions. The process is quantitatively linked to the pair-breaking nature of the proximity effect through the measured depression in $T_c$ caused by the normal electrode.

• Received 13 February 1984

DOI:https://doi.org/10.1103/PhysRevB.29.6384