Title :
NbN/TaNx/NbN SNS Josephson junctions by pulsed laser deposition
Author :
Kaul, Anupama B. ; Van Duzer, Theodore
Author_Institution :
Dept. of Mater. Sci. & Eng., California Univ., Berkeley, CA, USA
fDate :
3/1/2001 12:00:00 AM
Abstract :
We have made NbN/TaNx/NbN Josephson junctions with nonhysteretic I-V characteristics that may have potential application for single-flux-quantum logic or SQUID magnetometers. The trilayer growth was done in-situ using pulsed laser deposition. The resistivity of the TaNx was varied by the N2 pressure during growth from a few hundred micro-ohm-cm at low pressure to a few hundred milli-ohm-cm at pressures up to 300 mTorr. The films were characterized using Rutherford backscattering, X-ray diffraction, and atomic force microscopy. Junction processing was done in the usual trilayer technology. The fabricated Josephson junctions show IcRn values >0.3 mV at 4.2 K. We also observed that at a high laser fluence, NbN films with low a real particulate density and Tc~16.2 K could be grown on 25°C substrates
Keywords :
Josephson effect; Rutherford backscattering; X-ray diffraction; atomic force microscopy; electrical resistivity; niobium compounds; pulsed laser deposition; superconducting transition temperature; tantalum compounds; type II superconductors; 0.3 mV; 16.2 K; 25 C; 300 mtorr; 4.2 K; Josephson junctions; Junction processing; N2 pressure; NbN-TaN-NbN; NbN/TaNx/NbN SNS Josephson junctions; Rutherford backscattering; Tc; X-ray diffraction; atomic force microscopy; high laser fluence; nonhysteretic I-V characteristics; pulsed laser deposition; real particulate density; resistivity; trilayer growth; Atomic beams; Atomic force microscopy; Backscatter; Conductivity; Josephson junctions; Optical pulses; Pulsed laser deposition; SQUID magnetometers; X-ray diffraction; X-ray lasers;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
