Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 55: Poster Session: Superconductivity 2
TT 55.6: Poster
Mittwoch, 22. März 2017, 15:00–19:00, P2-OG3
Fast and highly sensitive read out electronics for micro-SQUIDS — •Sandra Gottwals1, Andreas Müller2, and Georg Schmidt1,3 — 1Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Fachgruppe Nanostrukturierte Materialien, Halle — 2Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Abteilung Elektronik, Halle — 3Martin-Luther-Universität Halle-Wittenberg, Interdisziplinäres Zentrum für Materialwissenschaften, Halle
We want to use Nb-based micro-SQUIDS [1] to measure the Spin-Nernst-effect [2]. For this purpose we need to read out the SQUIDS with high resolution and keep current induced heating as low as possible. We have developed a new electronics setup for readout which is based on two separate digital-to-analog converters (DACs) running at high speed but with different scaling. The first converter is used to run a current ramp which gives a course measurement of the critical current. In a second measurement the second DAC creates a ramp close to the critical current at very high resolution. Once the critical current is established this way it can be measured using a high resolution voltmeter or analog-to-digital converter. The dual setup allows to automatically detect a wide range of critical currents, and immediate shut-down when critical current is reached while at the same time giving a high resolution reading. The resolution is mainly determined by the final read-out device rather than by the resolution of the DACs.
[1] Wernsdorfer, Supercond. Sci. Technol. 22 (2009)
[2] Cheng, et. al., Phys. Rev. B 78 (2008)