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Measurement of Epitaxial NbN/AlN/NbN Tunnel Junctions With a Low Critical Current Density at Low Temperature.
- Source :
-
IEEE Transactions on Applied Superconductivity . Jun2011, Vol. 21 Issue 3, p135-138. 4p. - Publication Year :
- 2011
-
Abstract
- Superconducting qubit circuits require high quality low critical current density Josephson tunnel junctions. We have developed high quality epitaxial NbN/AlN/NbN tunnel junctions with critical current density, Jc, ranging from as low as a few A/cm^2 to a few tens of kA/cm^2. In this work, we measured current–voltage characteristics for junctions with a Jc\sim 32\ \rm A/cm^2 in the temperature range from 17 mK to above 6.7 K. All the junctions are in good quality and have a high gap voltage (>5.5 mV). We found that the junctions' sub-gap resistances were temperature dependent above 2.5 K and saturated at temperatures below 2.5 K. A junction sub-gap leakage current Ir of about 23 pA was measured. The voltage noise power spectral density for 3 junctions with different sizes has been measured at the base temperature of 17 mK with the junctions biased above the gap voltage. The spectral densities clearly show 1/f behavior at low frequency and are proportional to the junction's linear dimension. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10518223
- Volume :
- 21
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- IEEE Transactions on Applied Superconductivity
- Publication Type :
- Academic Journal
- Accession number :
- 60967768
- Full Text :
- https://doi.org/10.1109/TASC.2010.2081653