title: d-Wave-induced Josephson current counterflow in YBa2Cu3O7/Nb zigzag junctions.
abstract: Well-defined zigzag-shaped ramp-type Josephson junctions between YBa2Cu3O7 and Nb have been studied. The magnetic field dependencies of the critical currents provide evidence for d-wave--induced alternations in the direction of the Josephson current between neighboring sides of the zigzag structure. The arrays present controllable model systems to study the influences of pi facets in high-angle high- T(c) grain boundaries. From the characteristics, we estimate a possible imaginary s-wave admixture to the order parameter of the YBa2Cu3O7 to be below 1%.
authors.affiliation: Low Temperature Division, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: H J H
authors.initials: HJ
authors.lastname: Smilde
authors.lastname: Ariando
authors.forename: D H A
authors.initials: DH
authors.lastname: Blank
authors.forename: G J
authors.initials: GJ
authors.lastname: Gerritsma
authors.forename: H
authors.initials: H
authors.lastname: Hilgenkamp
authors.forename: H
authors.initials: H
authors.lastname: Rogalla