Specific heat of niobium-zirconium multilayers

We present the first specific-heat measurements of artificially layered superconducting structures. Using small sample calorimetry, we have measured the specific heat of Nb-Zr multilayers. Samples with $\Lambda$, the bilayer period, varying from 32.8 to 429 Å (with total sample thickness of 1.5 μm) were studied in a temperature range 1.5-20 K. We obtained the effective ${\theta }_D$ and $\gamma$ for the samples as well as $\frac{\Delta C}{\gamma T_c}$.