Homoepitaxial (110) YBa2Cu3O7-δ/YBa2(Cu1-xFex)3O7-δ/YBa2Cu3O7-δ SNS Junctions

We report on the first successful single crystal SNS junction based on (110) YBa2Cu3O7-δ (YBCO)/YBa2(Cu1-xFex)3O7-δ (YBCFeO: 150 nm)/YBa2Cu3O7-δ films grown on (110) YBCO single crystal substrates. The surface flatness is nearly the same level as good as (110) YBCO homoepitaxial films, as confirmed by Scanning Electron Microscopy, Reflection High Energy Electron Diffraction and Transmission Electron Microscopy observations. The single crystal SNS junction shows an anisotropic field dependence in large-junction behavior at 77 K. The field supression of critical supercurrent Ic(T) is greater than 95% at 77 K and 9.0 K. The temperature dependence of Ic(T) is well described by proximity SNS theory near the junction transition temperature Tcn, but exibits nearly T-linear behavior at low temperature.