High-TC thin SQUID film gradiometers on 5×5 mm2 bicrystal
M. L. Chuharkin1), O. V. Snigirev1), and S. A. Gudoshnikov2)
1) Physics Department, Moscow State University, Leninskie Gory 1, 119992, Moscow, Russia 2) Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, IZMIRAN, Troitsk, Moscow Region 142190, Russia
Abstract – Thin film dc SQUID gradiometers using a single YBa2Cu3O7-δ layer and grain boundary Josephson junctions on 30° SrTiO3 bicrystal substrates have been prepared. The planar gradiometer consists of two pickup loops galvanically coupled to the two small area SQUIDs with inductances of about of 30 pH and 45 pH. The gradiometric balance close to 500 has been obtained with base 2.3 mm. White noise level about 7 μΦ0/Hz1/2 or 2 pT/cm∙Hz1/2 in unshielded environment at 77 K. |