Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 99: Poster Session: Transport
TT 99.39: Poster
Donnerstag, 15. März 2018, 15:00–19:00, Poster B
Switching Current Distributions of Granular Aluminum micro-SQUIDs — •Felix Friedrich1, Patrick Winkel1, Hannes Seeger1, Nataliya Maleeva1, Christoph Sürgers1, Ioan M. Pop1, and Wolfgang Wernsdorfer1,2,3 — 1PHI, Karlsruhe Insti- tute of Technology (KIT), Karlsruhe, Germany — 2INT, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany — 3Institut Néel, CNRS, Grenoble, France
Granular aluminum (GrAl) is a strongly disordered superconductor consisting of nm-sized aluminum (Al) grains separated by aluminum oxide (AlOx) tunnel barriers. The material shows both increased critical temperature and critical field compared to pure Al. Furthermore, its high kinetic inductance makes GrAl interesting for e.g. high inductance superconducting detectors or circuits [1]. In order to obtain a better understanding, we performed transport measurements in GrAl micro-SQUIDs and will present first results. We measure IV curves and analyze switching current distributions as a function of temperature, current sweep rate, as well as in- and out-of-plane magnetic field. Our micro-SQUIDs have loop areas in the order of 1 µm2 and are interrupted by constrictions with a few 100 nm length and less than 100 nm width. We find strong deviation from the standard RCSJ-model that we try to relate to the granular nature of the junctions. As the grain size is much smaller than the junctions’ dimensions, we expect Josephson junction arrays formed from the coupled Al/AlOx grains to define the switching current modulation.
H. Rotzinger, et al., Supercond. Sci. Technol. 30, 025002 (2017)