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Superconducting properties of NbN film, bridge and meanders

IR@NPL: CSIR-National Physical Laboratory, New Delhi

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Title Superconducting properties of NbN film, bridge and meanders
 
Creator Joshi, Lalit M.
Verma, Apoorva
Gupta, Anurag
Rout, P. K.
Husale, Sudhir
Budhani, R. C.
 
Subject Materials Science
Applied Physics/Condensed Matter
Nanoscience/ Nanotechnology
 
Description The transport properties of superconducting NbN nanostructures in the form of thin film, bridge of width (w) = 50 mu m and three meanders of w = 500, 250 and 100 nm have been investigated by resistance (R) measurements in temperature (T) range = 2 - 300 K and magnetic field (B) range = 0 - 7 Tesla. The nanostructuring was carried out using Focused Ion Beam (FIB) milling. Reduction of sample width results in significant changes in the normal and superconducting state properties. For instance, the observed metallic behavior in the thin film sample is lost and the normal state resistance increases drastically from 2.4 Omega to 418 k Omega for the 100 nm meander. In the superconducting state, the value of critical temperature T-c (upper critical field B-c2 at T = 0 K) reduces gradually with width reduction, it changes from 13.15K(42.8 Tesla) in the case of thin film sample to 5.7K(12.7 Tesla) for the 100 nm meander sample. The superconducting transitions are found to get broader for the bridge sample and the meanders additionally show low-temperature resistive tails. In case of all the samples with reduced width, the transition onsets are found to be rounded at surprisingly high values of T similar to 25K > > T-c. These results are discussed in terms of the possible effects of FIB processing and weak localization in our samples.
 
Publisher American Institute of Physics
 
Date 2018-05
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://npl.csircentral.net/3739/1/Superconducting%20properties.pdf
Joshi, Lalit M. and Verma, Apoorva and Gupta, Anurag and Rout, P. K. and Husale, Sudhir and Budhani, R. C. (2018) Superconducting properties of NbN film, bridge and meanders. AIP Advances, 8 (5). 055305-055313. ISSN 2158-3226
 
Relation http://npl.csircentral.net/3739/