The results of a computer simulation and experimental study of the magnetoimpedance effect (MI) in amorphous Co68.5Fe4.0Si15.0B12.5 and Co68.6Fe3.9Mo3.0Si12.0B12.5 ribbons in the ac frequency range from 0.01 to 100 MHz are presented. It was found that the maximum MI value exceeds 200%, which may be of interest in the development of magnetic field sensors. It is also shown that practically significant characteristics of the MI response strongly depend on the ac frequency, which is due to the inhomogeneous distribution of magnetic properties over the ribbon cross section. This distribution was studied using magnetoimpedance tomography based on the analysis of the experimental dependences of the reduced impedance on the ac frequency.
Keywords: amorphous magnetically soft alloys; computer simulation; finite element method; magnetoimpedance effect; magnetoimpedance tomography.