Noise characteristics of YBa2Cu3O7−δ /CaRuO3/YBa2Cu3O7−δ Josephson junctions

Abstract

The noise characteristics of YBa2Cu3O7−δ/CaRuO3/YBa2Cu3O7−δ edge junctions are reported. The junctions exhibit low 1/f noise in the range of operating temperatures from 65 to 77 K. At lower temperatures the level of 1/f noise increases, and in addition, telegraph noise dominates the noise power spectrum at discrete current biases that are junction dependent. The characteristic frequency of a particular switching process increases with temperature but may increase or decrease with increased bias current. These results are consistent with a description of the superconductor-metal interface in which oxygen deficiency and/or disorder gives rise to localized states which trap carriers and lead to noise in the junction transmission.