Fabrication and properties of superconducting device structures in YBa2Cu3O7-xthin films

Publisher Website
Google Scholar
Abstract
The authors report the results obtained from thin-film superconducting tunnel-junction structures in high-transition-temperature materials. Two classes of structure have been studied; firstly that in which a single layer of YBa2Cu3O7-x is overlain by cross strips of Nb, and secondly multilayer high-critical-temperature YBa2Cu3O7-x superconducting thin films that incorporate an Y2O3 artificial barrier. Preliminary device structures prepared from the samples incorporating this artificial barrier have demonstrated distinct Josephson supercurrents in these materials, although only at this stage for tunnelling through the 'natural' tunnel barriers that commonly form between neighbouring high-Tc grains. Experiments also indicate the survival of the artificial tunnel barrier. The results obtained with the Nb strips provide a measurement of a superconducting energy gap in the high-Tc material which is consistent with values previously reported in La-based high-Tc materials.