Thermodynamics of the Proximity Effect: Specific-Heat Jumps in Lamellar Lead-Tin Eutectic Alloys

Abstract

The specific-heat jump at the critical temperature has been determined as a function of $D_S$, the thickness of the superconducting layers. For thick layers, the jump decreases rapidly as $D_S$ decreases, approaching a limit of about one-half the bulk value. A second jump in the specific heat (associated with the transition in the "normal" layers) decreases rapidly as the normal-layer thickness decreases, and extrapolates to zero for $D_N\approx \frac{1}{4}\mu$.