SHUNTED BICRYSTAL JOSEPHSON-JUNCTIONS ARRAYS FOR VOLTAGE STANDARDS

Series arrays of 365 shunted YBa2CU3O7-x Josephson junctions on yttria -stabilized zirconia bicrystals were investigated under microwave irra diation in the K-band. Sub-arrays of up to 39 junctions were synchroni zed to the external microwave power at a temperature of 15 K. Although there was a considerable spread in the critical currents of the junct ions and in the microwave bias current distribution, a first Shapiro s tep with a height of 30% of the total critical current of the sub-arra y was obtained by using an external shunt resistor, thus reducing the spread in normal resistances to 5%. Such high-T-c cryoelectronic circu its are applicable for voltage standards and precision digital-analog converters. (C) 1996 American Institute of Physics.