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TT: Fachverband Tiefe Temperaturen

TT 35: Superconducting Electronics: SQUIDs, Circuit QED

TT 35.3: Vortrag

Mittwoch, 20. März 2024, 10:00–10:15, H 2053

Development of ultrasensitive dc SQUIDs with sub-micrometer circuit elements — •Mauro Esattore¹, Michael Paulsen², Jörn Beyer², Mark Bieler¹, Oliver Kieler¹, Patryk Krzysteczko², and Rainer Körber² — ¹Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany — ²Physikalisch-Technische Bundesanstalt, Abbestraße 2-10, 10587 Berlin, Germany

Since its first iteration in the early 1960s, the direct current Superconducting QUantum Interference Device (dc SQUID) has been one of the most sought-after applications of superconductor technology. Its sensitivity to even the smallest magnetic fields allows for numerous applications, be it as a magnetometer in the fields of biomagnetism, magnetic flux sensor of cryogenic detectors, or for electrical metrology. In this presentation, we discuss the use of superconductive, sub-micrometer fine-pitch coils to be used in Nb/AlOx/Nb SQUID designs. The aim is to minimize the inductive losses of the signal-to-SQUID coupling, without compromising the overall device layout. It is also possible to achieve outstanding coupled energy resolution -while using the dc SQUID as a current sensor- by adapting the input coil inductances to the impedance of the signal source. Finally, the sub-micrometer input coils allow for a much lower noise energy per bandwidth є (є ≈ 16k_B T√LC under optimum conditions) as well as a wider range on input inductances for existing sensor types. We provide an overview of the fabrication process of the sub-micrometer fine-pitch coils, and some preliminary characterization results.

Keywords: Superconductivity; SQUIDs; Sub-micrometer; Fabrication; Low temperature