SKM 2023 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 58: Poster: Superconductivity II
TT 58.5: Poster
Donnerstag, 30. März 2023, 15:00–18:00, P2/OG3
Recent insights into low frequency excess flux noise in superconducting quantum devices — •Anna Ferring-Siebert, Fabian Kaap, David Mazibrada, Lukas Münch, Matthew Herbst, Andreas Fleischmann, Christian Enss, and Sebastian Kempf — Kirchhoff-Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany.
In many applications low frequency excess flux noise (EFN), with a frequency dependence of 1/fα, limits the performance of superconducting quantum devices such as SQUIDs and Qubits. Although it was long believed that its magnitude expressed in units of magnetic flux SΦ(1 Hz) and exponent α are fairly independent of the device material and inductance, there meanwhile exist hints for the contrary. It is also known that EFN can depend on the equipment used for device fabrication, the reason for that however remained unknown up to now.
In this contribution, we discuss origins of fabrication induced EFN as well as means to minimize it. In particular, we show that material layers deposited with commercial deposition equipment can contain magnetic impurities causing EFN. In this context, we present how we have modified commercial sputtering sources to reduce EFN and provide evidence for a relationship between EFN amplitude and the DC magnetization of the deposited material layers. Finally, recent measurements investigating the dependence of EFN on device inductance are discussed, suggesting that energy sensitivity ε(1 Hz) = SΦ(1 Hz)/(2L), rather than magnetic flux noise, is the more appropriate metric to describe EFN.