Evaluation of quality factors in superconductor microresonators with proximity enhancement

Author

Yong-Chao Tang ; Benningshof, Olaf W. B. ; Mohebbi, Hamid Reza ; Cory, David G. ; Guo-Xing Miao

Author_Institution

Inst. for Quantum Comput., Waterloo, ON, Canada

fYear

2014

fDate

18-21 Aug. 2014

Firstpage

347

Lastpage

351

Abstract

The quality factor of microstrip line resonators made of 20/50/20 nm Nb/NbN/Nb trilayer films has been calculated as microwave transmission through the cascade of three single layers, and in agreement with experimental data. Each layer is evaluated with an explicit extended Zimmermann expression. The formula is generalized from the standard expression by including electron mean free path and the imaginary part of the gap energy of the material [1]. The quality factor of the microresonator consisting of a 50 nm thick single layer Nb film is also calculated by this compact expression and quantitatively agrees with the measured results as well. The quality factor of the microresonator made of trilayer films is shown to be larger than that of the microresonator with only a single Nb film.

Keywords

Q-factor; electron mean free path; microcavities; micromechanical resonators; niobium; Nb-NbN-Nb; Q-factors; compact expression; electron mean free path; explicit extended Zimmermann expression; gap energy; microwave transmission; proximity enhancement; quality factors; size 50 nm; standard expression; superconductor microresonators; trilayer films; Impedance; Niobium; Superconducting epitaxial layers; Superconducting microwave devices; Superconducting transmission lines; Surface impedance; Surface resistance; Surface impedance; microresonator; proximity effect;

fLanguage

English

Publisher

ieee

Conference_Titel

Nanotechnology (IEEE-NANO), 2014 IEEE 14th International Conference on

Conference_Location

Toronto, ON

Type

conf

DOI

10.1109/NANO.2014.6968001

Filename

6968001