YBaCuO/PrBaCuO/YBaCuO trilayer junctions with the etched YBaCuO base electrodes

Abstract

Trilayer junctions are attractive for digital electronic applications, but superconducting wiring layers and contacts are required to fabricate the circuits. If the contact areas in this device structure are able to become Josephson junctions, YBaCuO films as counter electrodes can be used as the wiring layers; the fabrication process will become simple as that of ramp-edge type junctions. Thus, we tried to fabricate Josephson junctions on etched surface of YBaCuO films. Ar-ion milling was performed on YBaCuO film grown on a vicinal SrTiO 3(0 0 1) substrate by RF magnetron sputtering. After that, PrBaCuO film with 15 nm thickness and YBaCuO film were consecutively deposited on the etched surface of the YBaCuO film as base electrodes. The junctions with the size of 10 μm×10 μm showed resistively shunted junction-like I–V curves with the critical current of 0.12 mA.