Response of Nb-aSi-Nb junctions to 604 GHz radiation

Conference · Fri Mar 01 04:00:00 EST 1985 · IEEE Trans. Magn.; (United States)

OSTI ID:6462090

Danchi, W C; Free, J U; Habbal, F; Tinkham, M

We have measured the response of Nb-aSi-Nb junctions to 604 GHz radiation from an optically pumped far-infrared (FIR) laser source. These rugged and thermally cyclable junctions situated at the midpoint of 180 ..mu..m long dipole antennas, were fabricated on oxidized silicon wafers using the Selective Niobium Anodization Process (SNAP). Josephson current densities were about 9,000 A/cm/sup 2/, the McCumber parameters ..beta../sub c/ were about 3.5, and the Josephson plasma frequencies ..omega../sub J/ about 2.5 x 10/sup 12/. On a junction with a normal state resistance of about 7..cap omega.., we observed three Josephson steps and one photon-assisted tunneling step. The widths of the Josephson steps were studied as a function of the laser power. An RSJ model computer simulation with a nonlinear quasiparticle conductance and an RF current bias (assumed because of the low junction resistance) is able to account reasonably well for the laser-power dependence of the critical current (zeroth step) and the second step. However, the temperature dependence is more complex, and a discrepancy still exists between the RSJ model calculation and the data for the hysteretic first step.

• Research Organization: Physics Department and Division of Applied Sciences, Harvard University, Cambridge, MA
• OSTI ID: 6462090
• Report Number(s): CONF-840937-
• Conference Information: Journal Name: IEEE Trans. Magn.; (United States) Journal Volume: MAG-21:2
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
COMPOSITE MATERIALS
COMPUTERIZED SIMULATION
FREQUENCY RANGE
GHZ RANGE
GHZ RANGE 100-1000
JOSEPHSON JUNCTIONS
JUNCTIONS
MATERIALS
MATHEMATICAL MODELS
NIOBIUM ALLOYS
PERFORMANCE
SILICON ALLOYS
SIMULATION
SUPERCONDUCTING COMPOSITES
SUPERCONDUCTING JUNCTIONS
TEMPERATURE DEPENDENCE