Aging phenomena of plasma oxidized Pb‐alloy Josephson junctions

摘要

Aging phenomena in I‐V characteristics of plasma oxidized Pb‐alloy Josephson junctions have been investigated. Aging effect, or decrease in tunneling resistance during room‐temperature storage as long as 300 days, was found to be dominated by a single rate‐controlling process of activation energy of 0.78 eV. Based on Auger analysis of tunneling layers, it was concluded that the aging effect can be attributed to the compositional variation in the tunneling oxide layer resulting from the conversion from a Pb‐ and In‐oxide mixture into In oxide. A simple phenomenological model is proposed, which well explains the decrease in tunneling resistance upon aging.