Effective area reduction in directly coupled superconducting quantum interference device based micromagnetometers

We have designed and tested a set of YBa2Cu3O7- YBCO directly coupled superconducting quantum interference devices SQUIDs. The proposed layout introduces a reduction of the device effective area that leads to high design flexibility for micromagnetometer sensors. SQUID magnetometers have been realized using YBCO grain boundary junctions fabricated on symmetric 30° 001 bicrystal substrates. Sensors have been characterized in a highly shielded environment confirming theoretical predictions.