Scaling behavior of 1/f noise in high-temperature superconductor Josephson junctions

Extensive studies of the low frequency 1/f noise in high-temperature superconducting (HTS) Josephson junctions of various types and materials have been performed for a wide range of operating parameters. The origin of the measured voltage fluctuations can be traced back to the trapping and release of charge carriers in trapping centers in an insulating barrier, giving rise to correlated fluctuations of the junction critical current I_c and normal-state resistance R_n. We observed a linear dependence of the normalized critical current and resistance fluctuations on R_n, which suggests a constant density of trapping centers for the HTS Josephson junctions. The scaling of the normalized fluctuations is in good agreement with the previously found scaling relation I_cR_n∝1/R_n and supports a junction model assuming a leaky tunnel barrier.