Effect of the magnetic-field orientation on the modulation period of the critical current of ramp-type Josephson junctions

We have investigated the dependence of the critical current I-C on the valu e and orientation of an externally applied magnetic field H for interface-e ngineered YBa2Cu3O7-x ramp-type Josephson junctions. The results are compar ed with measurements of Nb ramp-type junctions with a PdAu interlayer. The I-C versus H dependences are similar to Fraunhofer patterns and their modul ation period changes several orders of magnitude with the orientation of th e magnetic field. For both junction types, the dependence of the modulation period on the orientation of the magnetic field can be well described by t he change of the relevant projection of the junction area and the influence of flux-focusing. Therefore the features of the I-C(H) curves have to be a ttributed to the ramp geometry and not to specific properties of the superc onducting material. (C) 2001 American Institute of Physics.