Rapidly solidified CoFeSiBCr amorphous wire: From manipulation to giant magnetoimpedance sensor applications

Amorphous wires of nominal composition Co₆₆ Fe₂ Si₁₃ B₁₅ Cr₄ were prepared by in-water quenching technique. The effect of process parameters such as wheel speed, ejection pressure, ejection angle, dwell time etc. on preparation of the wire was examined carefully. The amorphicity of the wire was verified by X-ray diffraction (XRD). Crystallization study was carried out by Differential Scanning Calorimetry (DSC). Subsequently, the crystallization kinetics was analyzed by modified Kissinger expression and from the slope of the Kissinger plot, the activation energy was calculated and found to be 139 KJ/mol. The giant magnetoimpedance (GMI) properties were studied using automated GMI measurement system. The GMI controlling parameters like driving frequency of the ac, rms value of ac and applied static magnetic field (H_dc) etc were found to display a sensitive change in GMI properties at an optimal frequency of 5 MHz and driving current of 5 mA_rms. The influence of these controls on the output parameters of GMI like GMI_max, single peak (SP) to double peak (DP) transition, GMI field sensitivity (ξ) etc. throws light on the potential application of the wires for sensors.