The sensitive magnetoimpedance effect in Fe-based soft ferromagnetic ribbons

A comprehensive analysis of magnetoimpedance (MI) phenomena in Fe-based nanocrystalline ribbons is presented in this paper. Giant MI responses have been observed in nanocrystalline samples annealed over the temperature range 490 and . More than 400% increases of the MI ratio were obtained both in and in ribbons. The sensitivity can reach a value larger than in the field range 3 - 7.2 Oe at 800 kHz for ribbons. No MI effect was observed in an as-quenched amorphous sample, because of its very low permeability. A mostly resistive feature was found in an as-quenched amorphous sample. The field dependences of the effective permeability show a typical transverse anisotropy property, and the development of the transverse anisotropy in naturally annealed Fe-based ribbons was analysed.