GMI field sensitivity near a zero external field in Co-based amorphous alloy ribbons: experiments and model

The giant magnetoimpedance (GMI) effect in Co₆₆Fe₄Ni₁Si₁₅B₁₄ amorphous ribbons was investigated, and the obvious blunt peaks of GMI curves were observed in a weak external magnetic field (0∼3 Oe). The shape of the blunt peaks could be changed by different treatments, such as changing the aspect ratio of the ribbons, premagnetization before magnetoimpedance measurement, and rapid heat-treatment, and the GMI sensitivity is improved. Based on the experimental results, a model in view of magnetostrictive energy is proposed to analyze the bluntness of the peak of the GMI curve and the process of transverse permeability varying with the external field near zero-field in the Co-based amorphous ribbons, and all the experimental results have good agreement with our model. (paper)