Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 19: Superconductivity: Poster Session
TT 19.40: Poster
Montag, 7. März 2016, 15:00–18:00, Poster D
Low frequency dielectric properties of amorphous AlOx — •Arnold Seiler, Saskia Meissner, Hannes Rotzinger, and Georg Weiss — Physikalisches Institut, Karlsruher Institut für Technologie
Tunneling systems (TS) are well known to dominate the low temperature properties of amorphous and disordered solids. In superconducting circuits they interact with resonators and qubits and limit their quality factors and coherence times.
We go further and want to know, whether the TS in the dielectric material used in these circuits were distributed according to the standard tunneling model. Therefore we investigate different plate capacitor geometries containing the same dielectric AlOx as used in qubits. With resonators and large capacitors we cover a broad frequency range to probe the dielectric response of the TS.
Here we present the low frequency measurements on capacitors of 0.25 mm2 and 1 mm2 down to 15 mK. Surprisingly the application of a magnetic field leads to a dramatic change of the dielectric response. In respect to glasses a similar effect is known the elastic response of from superconducting metallic glasses but was not expected in the dielectric behavior of an insulating material.