DOPED-TYPE COPLANAR JUNCTIONS IN THE BI2SR2CA1CU2O8+DELTA SYSTEM

We report on a vertical Josephson junction in the Bi2Sr2Ca1Cu2O8+delta (BSCCO) system, based on a bilayer structure. A highly resistive bott om layer of Bi2Sr2(Ca1-zGdz)Cu2O8+delta is deposited by DC-sputtering and covered by an undoped BSCCO layer with a T-c of typically 90 K. Ju nctions are formed by trenches patterned through the top layer into th e resistive bottom layer. We found that the critical current I-c of th e junctions is determined by the width of the grooves. Josephson coupl ing is demonstrated by Shapiro-like steps in the I-V curve up to a wid th of 0.8 mu m.