Novel design and operation of thin film high T/sub c/ magnetometer

The concept of a magnetometer based on the nonlinear magnetic properties of a high-T/sub c/ superconductor thin film was developed and tested. A novel detection method which allows microwave operation was tested. The superconductor, driven into the nonlinear regions by applying an amplitude-modulated magnetic field, generates a low-frequency field at the modulation frequency commensurate with the externally applied fields. The particular advantage of this system versus the superconducting quantum interference device (SQUID) alternative is the minimal processing of the superconducting material necessary to construct such a device. An electronic system which allows operation up to 2.4 GHz was tested with a YBCO thin film sample in a magnetometer configuration. A noise density of 15 nT/sup 1/2/ was measured.<
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