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(c)R(n) proportional to 1/R(n) and supports a junction model assuming a leaky tunnel barrier. (C) 1997 American Institute of Physics.