Interactions between bicrystal Josephson junctions in a multilayer structure

We have fabricate and studied a variety of devices based on stacked YBa/sub 2/Cu/sub 3/O/sub x/ bicrystal Josephson junctions in a multilayer structure. The proximity of the junctions in the two layers produces a large number of effects based on interactions between the junctions. Voltage locking and current locking were observed in the stacked junctions. The voltage locking is due to the ac path provided by a SrTiO/sub 3/ layer between the stacked junctions. The current locking is likely the result of a Josephson vortex interaction.