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Title: Degradation of superconducting Nb/NbN films by atmospheric oxidation.


Abstract not provided.

; ; ; ; ; ;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1051--8223; 647099
DOE Contract Number:
Resource Type:
Resource Relation:
Journal Volume: 27; Journal Issue: 4; Conference: Proposed for presentation at the IEEE Applied Superconductivity Conference held September 4-9, 2016 in Denver, Co.
Country of Publication:
United States

Citation Formats

Henry, Michael David, Wolfley, Steven L., Young, Travis Ryan, Lewis, Rupert M., Clark, Blythe, Brunke, Lyle Brent, and Missert, Nancy A. Degradation of superconducting Nb/NbN films by atmospheric oxidation.. United States: N. p., 2016. Web. doi:10.1109/TASC.2017.2669583.
Henry, Michael David, Wolfley, Steven L., Young, Travis Ryan, Lewis, Rupert M., Clark, Blythe, Brunke, Lyle Brent, & Missert, Nancy A. Degradation of superconducting Nb/NbN films by atmospheric oxidation.. United States. doi:10.1109/TASC.2017.2669583.
Henry, Michael David, Wolfley, Steven L., Young, Travis Ryan, Lewis, Rupert M., Clark, Blythe, Brunke, Lyle Brent, and Missert, Nancy A. Thu . "Degradation of superconducting Nb/NbN films by atmospheric oxidation.". United States. doi:10.1109/TASC.2017.2669583.
title = {Degradation of superconducting Nb/NbN films by atmospheric oxidation.},
author = {Henry, Michael David and Wolfley, Steven L. and Young, Travis Ryan and Lewis, Rupert M. and Clark, Blythe and Brunke, Lyle Brent and Missert, Nancy A.},
abstractNote = {Abstract not provided.},
doi = {10.1109/TASC.2017.2669583},
journal = {},
number = 4,
volume = 27,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2016},
month = {Thu Sep 01 00:00:00 EDT 2016}

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  • Niobium and niobium nitride thin films are transitioning from fundamental research toward wafer scale manufacturing with technology drivers that include superconducting circuits and electronics, optical single photon detectors, logic, and memory. Successful microfabrication requires precise control over the properties of sputtered superconducting films, including oxidation. Previous work has demonstrated the mechanism in oxidation of Nb and how film structure could have deleterious effects upon the superconducting properties. This study provides an examination of atmospheric oxidation of NbN films. By examination of the room temperature sheet resistance of NbN bulk oxidation was identified and confirmed by secondary ion mass spectrometry. Asmore » a result, Meissner magnetic measurements confirmed the bulk oxidation not observed with simple cryogenic resistivity measurements.« less
  • A novel approach to modulating the inductance of a superconducting microstrip is described. This approach could be the basis for numerous practical applications, such as phase shifters and high frequency tuning elements. The physical mechanisms involved are quasiparticle injection, gap suppression, and penetration depth modulation. In this current, the authors have investigated the modulation of the penetration depth of niobium and niobium nitride films by excess quasiparticle injection. To this effect, all-niobium and all-niobium-nitride SQUID circuits are designed and fabricated. These circuits allow quasiparticle injection into the inductive element of the SQUID. This injection is achieved by 1. optical irradiationmore » through an opening in a Nb reflective layer which partially masks the rest of the circuit, and 2. electronic current injection through a tunnel junction overlaid on the microstrip inductance. Penetration depth modulation is achieved with both methods. The magnitude of the effect varies from 10% to over 200% change in inductance. These results and their dependence on temperature and on the parameters of the control mechanism (light intensity, amount of current injection, etc.) are presented and discussed.« less
  • Amorphous Nb{sub 2}O{sub 5} thin films are obtained from the thermal oxidation in air at 300{degrees}C of magnetron-sputtered NbN{sub {ital x}} on transparent electrodes. Their optical transmittance is of the order of 80% in the visible wavelength range, and their optical gap is 3.9 eV. Quality of oxide films is directed by the density of the initial NbN{sub {ital x}} film. Electrochemichromic (ECC) behavior of these films is studied in aqueous H{sub 2}SO{sub 4} solution. Reversible optical changes are observed between {minus} 0.8 and 0.2 V {ital vs}. saturated calomel electrode. Optical densities over unity are obtained at lower voltage.more » Voltammetric, chronoamperometric, and ac impedance measurements have been performed in order to understand better the mechanism of this process. Experimental results are discussed in the frame of a theoretical model for the insertion of species in thin plane metallic films.« less
  • The optimum conditions for synthesizing Nb and NbN films by rf cathode sputtering are studied. The dependence of the critical temperature T/sub c/ on the film thickness which is observed for these films can be attributed to the proximity of the film to a surface layer with a relatively low value of T/sub c/.
  • The ultrasonic attenuation of 600-700 MHz surface acoustic waves by two high T/sub c/, cubic crystal structure, superconducting thin films has been investigated. The films studied were two, 0.5 thin, Nb/sub 3/Sn samples, electron-beam codeposited on LiNbO/sub 3/ and Quartz, and eleven NbN samples from 3 x 10/sup 3/ angstrom to less than or equal to 200 angstrom thin, sputter deposited on LiNbO/sub 3/. The Nb/sub 3/Sn (A15 structure) film on Quartz was difficult to measure due to defects in the Quartz caused by the high deposition temperature (approx. =700/sup 0/C) used to make the high T/sub c/ formmore » of the compound. The Nb/sub 3/Sn film on LiNbO/sub 3/, however, provided information about the transition temperature and energy gap at T = 0 K when the attenuation was measured as a function of temperature in zero magnetic field. A theory is developed to predict the electron-phonon produced normal state attenuation of surface acoustic waves by a thin, loss producing film on a nonattenuating substrate. Using a viscous drag model for the attentuation, the predictions of the theory are compared to the measured normal state attenuation to find the electron mean-free-path for the Nb/sub 3/Sn film on LiNbO/sub 3/.« less