Parametric controls on giant magnetoimpedance (GMI) behaviour of CoFeSiBCr amorphous wires for prospective sensor applications

Investigation is focused on the effect of different parametric controls like driving frequency, amplitude of the alternating current (ac), direct current (dc) bias field and anisotropy field (Hk) on the Giant Magneto-Impedance (GMI) properties of rapidly quenched soft magnetic Co66Fe2Si13B15Cr4 amorphous wires developed by in-water quenching technique. Optimal controls of these parameters like driving frequency and amplitude of the ac were found to display a sensitive change in GMI properties at optimal frequency of 5 MHz and 5 mA driving current. The influence of these controls on the output factors like maximum GMI ratio (GMImax), transition from single peak (SP) to double peak (DP), field sensitivity of GMI (η) and anisotropy field (Hk) throw light on the application of the developed wires for sensors. In addition to high Hk, driving frequency of 5 MHz also delivered a combination of desirable sensor properties like high level of sensitivity and its enhanced span of stability. Joule heating further improved the GMI response of the material through current annealing at a current density of 5 A/mm2.