Single-core Giant Magnetoimpedance with AC Bias

Enormous improvement of the temperature stability of simple giant magnetoimpedance (GMI) sensor has been reached by means of AC bias of the sensor. Despite of reduction of the frequency range of the sensor to less than 50 Hz, the 100 Hz-current flowing through the bias coil improves the temperature offset stability by the factor of 19; from 1053 nT/K to 54 nT/K (sinewave excitation current of 10 mA_RMS was used). The offset drift was furthermore reduced to less than 16 nT/K by increasing the amplitude of the excitation current to 24 mA_RMS.