Low hysteretic behavior of Al∕AlOx∕Al Josephson junctions

Abstract

All-aluminum Josephson junctions with high-transparency barriers were fabricated using the shadow-evaporation technique and measured at low temperatures, T≈25mK. Due to the high junction transparency, the IV characteristics showed only small hysteresis with a retrapping-to-switching current ratio of up to 80%. The observed critical currents were as large as 80%-100% of the Ambegaokar-Baratoff values. High barrier quality was confirmed by the low subgap leakage currents in the quasiparticle branches, which makes the low hysteretic Al junctions promising for application in integrated rapid single-flux quantum - qubit circuitry.