Feasibility of a Giant MagnetoImpedance Sandwich magnetometer for space applications

Space experiments require very efficient magnetic field sensors. Until now, fluxgate remains the most competitive way to measure weak magnetic field in space in spite of some drawbacks, like their offset drift. Since few years, giant magneto-impedance (GMI) effect were intensively studied and have shown promising results. Thus, we present a new GMI sandwich magnetometer for space application. The GMI sandwich transducer was fabricated with nanocrystalline alloy films and copper film. Very low noise amplifier is combined with an AM demodulation to extract weak dc-low frequency magnetic field from carrier. Noise equivalent magnetic induction (NEMI) is improved thanks to an experimental optimization method enables to increase the intrinsic sensitivity and use of a ratio transformer optimization to reduce noise electronic. We have obtained a flat transfer function in the frequency range [DC-1 kHz]. In this broad range, sensitivity is equal to 1000 V/T and NEMI reaches few nT/sqrt(Hz).