Development of a Josephson Junction-Based Superconducting True-Field Magnetometer

We have designed and fabricated a new range of thin-film superconducting true-field magnetometers (TFM) for use in detecting the true value of the magnetic field. Our TFMs enhance the applied magnetic field sensed at a Josephson junction by up to 70 times, as confirmed by a significant compression of the critical current versus magnetic field (Fraunhofer) characteristic. The resulting magnetic field sensitivities demonstrated were ~2 pT/radicHz. We compare the device parameters and performance at 77 K of several TFMs for two basic designs fabricated from thin films of YBCO.