Soft magnetic properties and giant magneto-impedance effect of Fe-Zr-Nb-B-Cu ribbons

摘要

The soft magnetic properties and the giant magneto-impedance (GMI) effect have been studied in Fe84Zr3.5Nb3.5B8Cu ribbons. The annealed samples with nanocrystalline structure show excellent soft magnetic properties and induced transverse anisotropy. The effective permeability is found to reach a maximum for the sample annealed at 923 K for 20 min. The maximal magneto-impedance ratio ΔZ/Z (ΔZ/Z = (Z(H)-Z(Hmax))/Z(Hmax)) of about 383% and the maximal sensitivity (i.e. the maximal value of the derivative of the ΔZ/Z-HL curve) of about 0.91% (A m-1)-1 (72% Oe-1) are measured at frequency f = 2.5 MHz for the same sample. The excellent soft magnetic properties and the induced transverse anisotropy are the basis of obtaining the sensitive magneto-impedance response. The intrinsic mechanism of the influence of the soft magnetic properties on the GMI effect is discussed briefly.