Abstract Body

We report on Hybrid Superconducting Quantum Interference Devices (HSQUIDs) developments and results obtained in collaboration between two laboratories of France and Turkey. HSQUIDs are superconducting devices which combine a Direct Current (DC) SQUID with a digital SQUID through a specific magnetic coupling scheme (see for instance Figure 1). The objective is to preserve as much as possible the ultimate and well-known sensitivity of DC SQUIDs, or analogue SQUIDs based on the Josephson tunneling effect [1], and combine it with a comparator-based [2] digital SQUID [3] relying on the Single-Flux-Quantum (SFQ) technique [4]. This is to allow the device to work under urban environment where strong magnetic pulse can happen at times, by increasing the dynamic range of the analogue SQUID.

We will present the principles of the chosen architectures, with the main properties and results, including underground measurements of the solar eclipse of 10 June 2021. We also measured the thermal noise-induced perturbations inside a closed-cycle GM cooler at 4.2K. A dynamic range of 7720 flux quanta was obtained in shielded environment, with a slew rate about 72 k/s for a sampling frequency of 100 kHz. At last we will present a detailed analysis of the specific pickup loops that were developed for the HSQUIDs.

References

[1] Josephson B 1962 Physics Letters 1(7) 251–3

[2] Myoren H et al 2017 IEEE Trans. Appl. Supercond.27 1-5

[3] Reich T, Febvre P, Ortlepp T, Uhlmann F H, Kunert J, Stolz R and Meyer H-G 2008 J. Appl. Phys. 104 024509

[4] Likharev K K and Semenov V K 1991 IEEE Trans. Appl. Supercond. 1(1) 3–28

Acknowledgment

This work has been partly supported by by the Fonds européen de développement régional (FEDER) in the frame of the LSBB2020 project, the CNES French National Space Agency and by the French-Turkish Partenariat Hubert Curien (PHC) BOSPHORE n°39708XA and TUBITAK under grant 117F266.

Keywords: Josephson junction, SQUID, DC SQUID, digital SQUID, SFQ, RSFQ