Superconducting Nb-film LC resonator

Authors :: Georg Eska
Rob Blaauwgeers
J. J. Ruohio
Antti Finne
I. Suni
Matti Krusius
R. Schanen
L. Groenberg
Vladimir Eltsov
Source :: Grönberg, L, Suni, I, Finne, A, Blaauwgeers, R, Eltsov, V, Eska, G, Ruohio, J, Schanen, R & Krusius, M 2001, ' Superconducting Nb-film LC resonator ', Review of Scientific Instruments, vol. 72, no. 9, pp. 3682-3686 . https://doi.org/10.1063/1.1394179
Publication Year :: 2001
Publisher :: American Institute of Physics (AIP), 2001.
Abstract: Sputtered Nb thin-film LC resonators for low frequencies at 0.5 MHz have been fabricated and tested in the temperature range 0.05--1 K in magnetic fields up to 30 mT. Their Q value increases towards decreasing temperature as sqrt(T) and reaches 10^3 at 0.05 K. As a function of magnetic field Q is unstable and displays variations up to 50%, which are reproducible from one field sweep to the next. These instabilities are attributed to dielectric losses in the plasma deposited SiO_2 insulation layer, since the thin-film coil alone reaches a Q > 10^5 at 0.05 K.<br />6 pages, 7 figures, submitted to Review of Scientific Instruments