Oscillations of the critical temperature and resistance in lamellar thin-film vanadium-carbon structures

The superconducting properties of vanadium-carbon sandwiches with vanadium layers d/sub V/=100 A thick and variable thickness carbon liners are studied. The thickness of the carbon liners was varied between 0 and 100 A. The investigations are performed with samples having one, two, and five vanadium layers. The dependence of the sandwich superconducting temperature T/sub c/ on the carbon liner thickness is oscillatory, the oscillations being particularly pronounced for the samples with two layers. The first peak on the T (d/sub C/) curve (d/sub C/ is the thickness of the carbon coating) occurs at d/sub C/=3 A for single-layer samples (vanadium film with carbon coating of variable thickness). In two- and five-layer sandwiches the first peak is observed for a carbon layer thickness of 5 A. A correlation is obtained between the critical temperature and the quantities R/sub 300//R/sub n/, rho/sub 300/, and rho/sub n/ for multilayer samples.