FUNCTIONAL-STUDY OF FLUXGATE SENSORS WITH AMORPHOUS MAGNETIC-MATERIALS CORES

A functional study of the TFS-3 type fluxgate sensor with amorphous ma gnetic material cores is made. The magnetic material used in these sen sors is Romanian amorphous material Co68.25Fe4.5Si12.25B15 thin ribbon produced at the Institute of Technical Physics, Iasi and prepared by rapid quenching from the melt on a rotating copper wheel. The sensor's functional parameters and thermostability were measured. The sensor s ensitivity is between 4.5 and 5.5 mu V nT(-1) and for fields greater t han 100 nT does not depend on temperature variation in the range + 20 to + 70 degrees C. Also the temperature variation does not influence t he noise of the sensor which does not exceed 600 pT(pp). The offset th ermostability corresponds to a thermal drift of 1 nT degrees C-1 over the whole mentioned temperature range. The ability of sensors to measu re a.c. magnetic fields by means of the two side bands of the second h armonic was studied using Fourier analysis. The study was done for a.c . field frequencies of up to 15 kHz, at excitation frequencies up to 3 0 kHz. For an induction field up to 26 mu T-pp the response is linear, showing the possibility of using the sensor for also measuring low fr equency a.c. fields. (C) 1997 Elsevier Science S.A.