Noise properties of granular NbN Josephson microbridges

Journal Article · Tue May 01 04:00:00 EDT 1984 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.333375· OSTI ID:5030102

Claassen, J H

The output noise of a granular NbN microbridge has been measured at frequencies near 25 MHz as a function of bias voltage, temperature, and rf bias at 70 GHz. It is generally greater than predicted by the resistively shunted junction model, but is significantly lower than has previously been observed in clean superconducting microbridges with comparable RI/sub c/ products. An estimate of the performance of the device as a Josephson mixer at 70 GHz is made on the basis of these measurements. At an operating temperature of 10 K a double sideband mixer noise temperature approx.200 K, with conversion loss of approx.3 dB should be attainable. Using the noise as a probe of the average temperature within the microbridge, it is found that simple self-heating is not a likely explanation for the disappearance of Josephson effects at high dc or microwave bias.

• Research Organization: Naval Research Laboratory, Washington, DC 20375
• OSTI ID: 5030102
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 55:9; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
JOSEPHSON JUNCTIONS
JUNCTIONS
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
NOISE
PERFORMANCE
PHYSICAL PROPERTIES
PNICTIDES
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS
USES