Abstract— New higher order gradiometer layouts based on high-temperature superconducting thin film bicrystal Josephson junctions are presented. Our single layer gradiometers are suitable for the simultaneous measurement of magnetic field gradients with different spatial orientations. The sophisticated technology for bicrystal Josephson junctions is combined with custom substrates with two crossing 30 degree grain boundaries. We present the technologically challenges focusing on the low ohmic contact resistance using gold nanoparticles embedded in the thin film. The sensor performance is characterized using a SQUID electronic, the main parameters e.g. the critical current and I_CR_N-product are compared with single dimension first order 30 degree bicrystal Josephson junction gradiometers. Special emphasis is put on the optimization of the noise properties in unshielded environment.

Index Terms—Antennas, Josephson junction, magnetic field measurement, noise, SQUIDs

Manuscript received 15 August 2008.
This work was supported in part by the project EU BIODIAGNOSTICS (017002).
P. Seidel, C. Becker, U Schinkel, K. Hoefer, V. Grosse, S. Engmann and  F. Schmidl are with the Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, D-07743 Jena, Germany (phone: +49-3641-947410; fax: +49-3641-947412; e-mail: Paul.Seidel@uni-jena.de).
A. Steppke, was with Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, D-07743 Jena, Germany. He is now with the Max-Planck-Institut für Chemische Physik fester Stoffe, D-01187 Dresden, Germany (e‑mail: Alexander.Steppke@cpfs.mpg.de).
L. Redlich is with the Institut für Photonische Technologien, D-07745 Jena, Germany (e-mail: lutz.redlich@ipht-jena.de).

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