Sample Length Dependence of Giant Magnetoimpedance in Fe–Zr–Nb–Cu–B Nanocrystalline Ribbons

Abstract

In the present work the sample length dependence of giant magnetoimpedance for Fe₈₄Zr_2.08Nb_1.92Cu₁B₁₁ nanocrystalline ribbons was investigated. With a reduction of sample length L, the peak field H_P of positive magnetoimpedance increases, due to an enhancement of demagnetization effect along the sample length direction. Meanwhile, a shortening of ribbon length brings about a decrease of the permeability change under field, which results in a drop of negative magnetoimpedance. In addition, the frequency f_max where the maximum of negative (ΔZ⁄Z₀)_max occurs, shifts to higher frequencies with reduction of sample length. The giant magnetoimpedance in nanocrystalline ribbons depends not only on the field and frequency, but also sensitively on the sample length, which should be considered in designing of GMI electronic circuits.