Design of magnetic sensor based on the asymmetric giant magneto-impedance effect in amorphous alloys

The soft magnetic properties of CoFeNiSiB amorphous alloy ribbon as sensing material were measured and analyzed. By the field-annealing heat treatment in air, a good asymmetric giant magneto-impedance effect(AGMI) has been obtained. A sensitive AGMI magnetic sensor was developed utilizing the field-annealed amorphous ribbon as sensing element, and the performance of the sensor was tested in open-loop and closed-loop conditions. The results indicate that the sensor shows a better sensitivity in the open-loop testing, and a better linearity and larger measurement range in the closed-loop testing. The designed sensor can be applied to detect the geomagnetic fields, which have good potential application in geomagnetic navigation.