SKM 2023 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 39: Superconducting Electronics
TT 39.10: Vortrag
Mittwoch, 29. März 2023, 17:45–18:00, HSZ 304
Mitigating losses in NbTiN superconducting circuits under magnetic fields. — •Arne Bahr, Matteo Boselli, Benjamin Huard, and Audrey Bienfait — Laboratoire de Physique - École normale supérieure de Lyon, France
Quantum superconducting circuits enable quantum information processing as well as quantum sensing at microwave frequencies. One predominant factor limiting their performance is the presence of impurities creating microwave losses, triggering intense research effort for their identification and mitigation[1]. Here we probe these impurities in the context of using superconducting circuits under magnetic fields, which has application for coupling to other spin systems[2] and also detecting electron spin resonance (ESR) at the few spin levels[3].
We report continuous wave ESR measurements on spin impurities in resonators fabricated in NbTiN on a sapphire substrate. A simple etch through a resist layer process results in the presence of many spin impurities, preventing any ESR measurement near the spin 1/2 line. Following the characterization and identification of these spin signals, we improve our fabrication process to remove these spurious spin signals so that the resonators exhibit internal quality factors above 5· 105 that remain constant up to 350 mT.
[1] N. P. de Leon et al., Science (2021)
[2] A. J. Landig et al., Nat. Com. (2019)
[3]V. Ranjan et al., Appl. Phys. Lett. (2020)