Optimized giant magnetoimpedance effect in amorphous and nanocrystalline materials

Abstract

This letter reports the giant magnetoimpedance (GMI) effect and its magnetic response in optimized Co70 Fe5 Si15 Nb2.2 Cu0.8 B7 amorphous and Fe71 Al2 Si14 B8.5 Cu1 Nb3.5 nanocrystalline ribbons. At a given frequency of 5 MHz, the largest GMI ratios of 513% and 640% were observed for the Co-based amorphous and Fe-based nanocrystalline samples, respectively. More interestingly, the magnetic response reached the largest value of 144%/Oe at the frequency of 4 MHz for the Co-based amorphous sample and of 40%/Oe at the frequency of 5 MHz for the Fe-based nanocrystalline sample. This is ideal for high-frequency and high-performance GMI-based sensor applications. The skin effect model was used to interpret the obtained results of GMI in connection with the magnetic-field and frequency dependences of the longitudinal permeability. © 2006 American Institute of Physics.