Effect of Dielectric and High-Resistivity Barriers on the Superconducting Transition Temperature of Thin Films

Increases in the transition temperature of a structure consisting of alternate 60-Å layers of superconductor $S$ and barrier material $B$ are observed whenever the sequence $\mathrm{SBS}$ is formed. The effect was observed for Al, Zn, In, Sn, and Pb and for a variety of barrier materials.