Berlin 2012 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 33: Superconductivity, Measuring Devices, Matter at Low Temperature: Poster Session
TT 33.44: Poster
Wednesday, March 28, 2012, 15:00–19:00, Poster B
Characterization of directly coupled YBa2Cu3O7−x SQUID magnetometers — •Alexander Guillaume, Verena Beister, Jan M. Scholtyssek, Frank Ludwig und Meinhard Schilling — Institut für Elektrische Messtechnik und Grundlagen der Elektrotechnik, Technische Universität Braunschweig, Hans-Sommer-Str. 66, D-38106 Braunschweig, Germany.
Superconducting Quantum Interference Devices (SQUIDs) can be employed as highly sensitive magnetic field sensors in a variety of applications such as magnetoencephalography or magnetic nanoparticle detection. We fabricated SQUIDs from the high-Tc superconductor YBa2Cu3O7−x on symmetric SrTiO3-bicrystal substrates by pulsed laser deposition and argon ion etching. The layout consists of two directly coupled magnetometers on one chip which are attached to a rectangular pickup loop.
The measurements were carried out in a liquid nitrogen container using a variable temperature insert. The temperature at the magnetically shielded sample holder can be adjusted between 77 K and 100 K.
Here, we present measurements of the I-V-curves under the influence of a magnetic field for different sample temperatures. Also, the influence of the temperature and the influence of the bias current on the V-Φ-curves were investigated. From these measurements, parameters of the SQUID were calculated and compared to the theoretical estimations. Additionally, noise spectra were recorded for different bias reversal frequencies by using a direct-coupled flux-locked loop electronics from Magnicon GmbH.