Homoepitaxial SNS Junctions Grown on YBCO Single Crystal Substrates

摘要

We report on the first successful single crystal SNS junction based on (110) YBa_2Cu_3O_(7-#delta#) (YBCO)/YBa_2(Cu_(1-x)Fe_x)_3O_(7-#delta#) (YBCFeO:150 nm)/YBa_2Cu_3O_(7-#delta#) films grown on (110) YBCO single crystal substrates. The surface flatness is enarly the same level as good as (110) YBCO homoepitaxial films confirmed by Scanning Electron Microscopy (SEM), Reflection High Energy Diffraction (RHEED) and Transmission Electron Microscopy (TEM) observations. The single crystal SNS junction shows an anisotropic field dependence in large junction behavior at 77 K. The field suppression of critical supercurrent Ic(T) is beyond 95 precent at 77 K and 9.0 K, which means small excess current of the single-crystallized junctions. In order to clarify the transport properties of N-layers, we also investigate YBa_2(Cu_(1-x)Fe_x)_3O_(7-#delta#) (YBCFeO:150 nm)/YBa_2Cu_3O_(7-#delta#) bilayered structures grown on (110) YBCO single crystal substrates. We did not observe manifest Fe diffusion at the YBCFeO/YBCO interface by the Secondary Ion Mass Spectrometry (SIMS) analysis.