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TT: Fachverband Tiefe Temperaturen
TT 31: Superconducting Electronics: SQUIDs, Qubits, Circuit QED, Quantum Coherence and Quantum Information Systems 1
TT 31.8: Vortrag
Mittwoch, 18. März 2020, 11:30–11:45, HSZ 03
Kinetic Inductance of thin Al Films using a Resonant Circuit — •Lorenz Fuchs, Christian Baumgartner, Dieter Schuh, Nicola Paradiso, Dominique Bougeard, and Christoph Strunk — Institute for Experimental and Applied Physics, University of Regensburg
Direct measurement of the magnetic penetration depth λ on thin films with a thickness d ≪ λ has been challenging ever since. We use a resonant circuit to determine the complex impedance of a superconducting thin film meander in the few MHz regime [1]. The meander is patterned into a 15nm thick aluminum film that is grown on a GaAs substrate. From the imaginary part of the impedance we determine the kinetic inductance of the superconducting condensate and from vortex motion in the pinning potential and from the real part a dissipative contribution caused by quasi-particle excitations and/or vortex motion. A small change of the total inductance of the system due to the kinetic inductance Lkin = µ0λ2/d of the superconductor below its critical temperature Tc leads to a significant decrease of the resonance frequency f0. The system is sensitive to changes of inductance smaller than 50 pH, which can compete with the accuracy of more standard two-coil mutual inductance techniques [2]. Examination of the basic features of this technique will provide the basis for further investigation of proximity induced superconductivity in InAs 2DEGs with large spin-orbit coupling.
[1] R. Meservey and P.M. Tedrow, J. Appl. Phys. 40, 2028 (1969)
[2] T. Lemberger et al., Phys. Rev. B, 76, 094515 (2007)