LAUSR

Abstract The recent work is focused on the development of suitable amorphous ferromagnetic microwires (CoFe-based) for use in giant magneto-impedance (GMI) magnetic sensing cores. Rapid solidification route is used for the preparation of microwires via in-rotating water quenching technique. The potential of the CoFeSiBCr soft magnetic microwires for GMI based sensing core is investigated by using the driving frequency of MHz range. The GMI characteristics of the developed materials are carried out via impedance-mode. The performance of the magnetic sensor is studied based on its maximum GMI ratio, magnetic field sensitivity and noise spectrum. The experimental results reveal that the maximum GMI ratio, GMImax of about 650% and field sensitivity of around 802 V/T is achieved at ac driving frequency of 5 MHz with 3 mA driving current when annealed at 750 K for 5 min. The noise level of the optimized microwire can be obtained under 10 nT/√Hz@1 Hz while driven at 5 MHz. By means of its high operating frequency regime, high sensitivity, low noise level and simple methodology for sensing, the GMI microwires working in impedance-mode can be a potential candidate for commercial sensing applications such as microfluxgate sensors.