Title :
Noise in DC SQUIDS with Nb/Al-oxide/Nb Josephson junctions
Author :
Cromar, M.W. ; Beall, J.A. ; Go, Diane ; Masarie, K.A. ; Ono, R.H. ; Simon, R.W.
Author_Institution :
Nat. Bur. of Stand., Boulder, CO, USA
fDate :
3/1/1989 12:00:00 AM
Abstract :
The authors have developed a process which incorporates very-high-quality Nb/Al-oxide/Nb Josephson junctions. The junctions had low subgap conductance, yielding Vm greater than 50 mV for critical current densities of 1000 A/cm2. Low-inductance SQUIDS (superconducting quantum interference devices) made with these junctions were apparently free from junction conductance fluctuations, at least for frequencies above 1 Hz. A correlation between low leakage junctions and low noise from critical current fluctuations was observed. The SQUIDS exhibited flux noise with an unusual frequency dependence of currently unknown origin
Keywords :
Josephson effect; SQUIDs; aluminium compounds; critical current density (superconductivity); niobium; Nb-AlOx-Nb; SQUIDS; critical current densities; flux noise; frequency dependence; junction conductance fluctuations; low leakage junctions; noise; subgap conductance; Critical current; Critical current density; Fluctuations; Frequency; Interference; Josephson junctions; Niobium; SQUIDs; Superconducting device noise; Superconducting devices;
Journal_Title :
Magnetics, IEEE Transactions on
