Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 18: Superconductivity: Poster

TT 18.31: Poster

Montag, 18. März 2024, 15:00–18:00, Poster C

YBCO Josephson junction arrays and resistors made by focused Helium ion beam irradiation — •Moritz Meichsner, Christoph Schmid, Dieter Koelle, Edward Goldobin, and Reinhold Kleiner — Physikalisches Institut, Center for Quantum Science and LISA+, Universität Tübingen, Germany

We use focused-helium-ion-beam (He-FIB) irradiation to “write” different devices in epitaxially grown YBa₂Cu₃O₇ thin films. The He-FIB irradiation changes the local properties of the YBCO film on the nanoscale – in particular, it can produce locally normal conducting or even insulating regions in the YBCO film. For example, by scanning with the He-FIB along a single line across a lithographically prepatterned YBCO microbridge, we can produce Josephson Junctions [1]. When irradiating a larger area, we can fabricate resistors with Ohmic behavior that can be used in resonant circuits or as load resistors. Moreover, by writing several junctions next to each other one can realize Josephson junction arrays. In this work, the interaction of Josephson junctions in such arrays is investigated. To achieve better coupling between the junctions, a He-FIB resistor was fabricated in parallel to the array. Biasing this circuit by a dc current results in an additional ac current through the array, provoking junction synchronization.

[1] B. Müller et al., Phys. Rev. Applied 11, 044082 (2019).

Keywords: Josephson junction; Josephson array; YBCO; He-FIB