GMI effect of Fe73.5-xCrxCu1Nb3Si13.5B9 amorphous and nanocrystalline soft wires

Giant magneto-impedance, GMI, effect of Fe73.5-xCrxCu1Nb3Si13.5B9 (x=0 and 10) amorphous and nanocrystalline soft wires has been measured at the frequency range from 0.005 up to 5 MHz as a function of the varying DC axial field up to ±140 Oe. Thermal treatments (in conventional furnace and by current annealing, with and without applied stress) lead to partial devitrification and induced anisotropies; hence they exhibit enhanced soft magnetic behavior and modify the GMI response. The results obtained in the current-annealed samples, improved in comparison with those for samples annealed in furnace, are ascribed to the homogeneous structure as well as to the induced helical anisotropy. The influence of the sample length (1-8 cm long) on GMI as well as that of the induced anisotropies is analyzed considering the particular c-domain structure and magnetization processes of the wire