Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 51: Superconductivity: Tunneling, Josephson Junctions, SQUIDs
TT 51.3: Vortrag
Mittwoch, 9. März 2016, 15:30–15:45, H19
Development of Nb nanoSQUIDs based on SNS junctions for operation in high magnetic fields — •Viacheslav Morosh1, Benedikt Müller2, Maria Jose Martinez-Perez2, Oliver Kieler1, Thomas Weimann1, Alexander Zorin1, Reinhold Kleiner2, and Dieter Kölle2 — 1Physikalisch - Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig — 2Physikalisches Institut and Center for Quantum Science in LISA+, Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen
Investigation of the magnetization reversal of single magnetic nanoparticles requires SQUIDs with high spatial resolution, high spin sensitivity (a few Bohr magneton µB) and at the same time sufficient stability in high magnetic fields. We fabricated dc nanoSQUIDs comprising overdamped SNS sandwich-type (Nb/HfTi/Nb) Josephson junctions using optimized technology based on combination of electron beam lithography and chemical-mechanical polishing. Our nanoSQUIDs have Josephson junctions with lateral dimensions ≤ 150 nm × 150 nm, effective loop areas < 0.05 µm2 and the distance between the Josephson junctions ≤ 100 nm. The feeding strip lines of the width ≤ 200 nm have been realized. The nanoSQUIDs have shown stable operation in external magnetic fields at least up to 250 mT. Sufficiently low level of flux noise resulting in spin sensitivity of few tens µB/Hz1/2 has been demonstrated. A further reduction of the nanoSQUID size using our technology is possible.
This work was supported by the Deutsche Forschungsgemeinschaft (DFG).