Fabrication of interface-engineered Josephson junctions on sapphire substrates

Abstract We report on a process for fabricating YBCO interface-engineered junctions on sapphire substrates. The electrical properties of the junctions thus produced were investigated across a wide range of temperatures. The current-voltage characteristics approached the characteristic of the resistively shunted junction property at high temperatures. The I C R N products of the junctions displayed a quasi-linear property. The I – V characteristics showed Shapiro steps under irradiation at 12.3 GHz, and this is consistent with the Josephson relation. We predict that the interface-engineered Josephson junction on sapphire will be suitable for ractical use in high-frequency mixers after optimization of the fabrication process.