Preliminary results on tunnel junctions on YBCO bulk with an artificial barrier

YBCO-bulk based tunnel junctions employing a cadmium sulphide artificial barrier have been fabricated. Preliminary results on the role played by the CdS film thickness and different YBCO surface processing are discussed. dc Josephson effect has been detected in samples with a low tunneling resistance. The dependence of the critical current on the external magnetic field is reported.