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TT: Fachverband Tiefe Temperaturen
TT 48: Superconductivity: Tunnelling, Josephson Junctions, SQUIDs 2
TT 48.3: Talk
Wednesday, March 22, 2017, 15:30–15:45, HSZ 201
A niobium based three-axis vector nanoSQUID — •Katrin Meyer1, Maria José Martínez-Pérez1, Benedikt Müller1, Diego Gella1, Viacheslav Morosh2, Thomas Weimann2, Roman Wölbing1, Javier Sesé3, Oliver Kieler2, Reinhold Kleiner1, and Dieter Koelle1 — 1Physikalisches Institut and Center for Quantum Science (CQ) in LISA+, Universität Tübingen, Germany — 2Fachbereich Quantenelektronik, Physikalisch-Technische Bundesanstalt, Braunschweig, Germany — 3Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, Spain
We present the design, realization, and performance of 3-axis vector nanoSQUIDs [1]. They consist of three mutually orthogonal SQUID nanoloops (two magnetometers, one gradiometer) that allow simultaneous and independent detection of the three components of the vector magnetic moment of individual magnetic nanoparticles (MNPs). All three nanoSQUIDs are realized within an area of a few µm2 on a single chip. The devices are based on intrinsically shunted Nb/HfTi/Nb Josephson junctions and exhibit linewidths of ∼ 250 nm. Operation at 4.2 K in external magnetic fields up to ∼ 50 mT is demonstrated, with a flux noise below ∼ 250 nΦ0/Hz1/2 in the white noise limit. Depending on device geometry and MNP position, spin sensitivities down to below 100 µB/Hz1/2 are achieved. We also present approaches to extend operation to larger external magnetic fields and to improve the spin sensitivity.
[1] M. J. Martínez-Pérez et al., ACS Nano 10, 8308–8315 (2016).