Effect of lanthanum doping of YBaCuO electrodes on the characteristics of modified-interface edge junctions

With the aim of improving the interface-modification process - a standard technique for forming the barrier in high-temperature superconducting Josephson junctions, lanthanum doping of a YBaCuO electrode was successfully attempted in this study. Accordingly, it was confirmed that lanthanum doping significantly affects junction characteristics; that is, it produces a lower critical current density and higher normal state resistance. In other words, lanthanum doping increased the annealing temperature or time for the barrier-formation process. These effects are advantageous for the growth of the counter layer, and for high-temperature processes made after the junction fabrication, such as upper-layer groundplane integration. It was confirmed that the lanthanum doping of the base electrode has a significant effect on the junction characteristics. It was also found that the lanthanum doping produces benefits in terms of higher critical current and normal-state resistance product.