ANOMALOUS MAGNETIC DIFFRACTION OF BI2SR2CACU2O8 AG/PB SNS' JOSEPHSON-JUNCTIONS/

Proximity Josephson junctions have been formed on cleavage steps of Bi 2Sr2CaCu2O8 (BSCCO) single crystals. In-plane, BSCCO/Ag/Pb junctions o n such steps show RSJ-type Josephson behavior with supercurrent densit ies as high as 10(4) A cm(-2) and an I(c)R(n) product of 5 mV is obser ved as theoretically predicted for these junctions. However, c-axis, o ut-of-plane junctions exhibit no measurable Josephson coupling. Instea d, a BCS-like gap structure of 25 mV with a nonzero conductance at zer o bias is observed for this kind of junctions. Furthermore, magnetic f ield dependence of the critical current is studied at low temperatures . Magnetic diffraction pattern is anomalous and decays rapidly to zero with magnetic field at around 300 G. Possible explanations for the an omalous diffraction data have been proposed and discussed in detail.