Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 42: Quantum Coherence, Quantum Information Systems 2
TT 42.1: Talk
Wednesday, March 13, 2013, 15:00–15:15, H18
Magnetic hysteresis effects in superconducting coplanar microwave resonators — •D. Bothner1, T. Gaber1, M. Kemmler1, M. Grünzweig1, B. Ferdinand1, S. Wünsch2, M. Siegel2, P. Mikheenko3, T. H. Johansen3, D. Koelle1, and R. Kleiner1 — 1Universität Tübingen, Germany — 2Karlsruher Institut für Technologie, Germany — 3University of Oslo, Norway
We present experimental data regarding the impact of external magnetic fields on quality factor and resonance frequency of superconducting microwave resonators in a coplanar waveguide geometry. In particular we focus on the influence of magnetic history and show with the assistance of numerical calculations that the found hysteretic behaviour can be well understood with a highly inhomogeneous microwave current density in combination with established field penetration models for type-II superconducting thin films. Furthermore we have used magneto-optical imaging techniques to check the field distribution which we have assumed in our calculations. Finally, we demonstrate that and how the observed hysteretic behaviour can be used to optimize and tune the resonator performance for possible hybrid quantum sytems in magnetic fields [1].
[1] D. Bothner et al., Phys Rev. B 86, 014517 (2012)