Critical thicknesses for the transition from intermediate- to mixed-state behavior in superconducting thin films of Pb,Sn, and In

Recent direct observations of the magnetic structure in thin films of Pb, Sn, and In are discussed relative to resistance measurements on the same films and to earlier experimental and theoretical work on thin films. Comparison to the theoretical results of Maki and Lasher is made and it is found that these results predict reasonably accurately the critical thickness separating intermediate-and mixed-state behavior in the thin films studied. This implies that the critical thickness has been overestimated in earlier work on similar films. It is suggested that this accounts, in part, for the high values obtained for the pure, bulk Ginzburg-Landau parameter in those experiments.Work supported by the National Science Foundation under Grant No. GN34125 and also under Grant No. GH33637 through the facilities of the Material Science Center, Cornell University.The work reported here represents part of a Ph.D. thesis submitted to the Graduate School Faculty of Cornell University, Ithaca, New York.