Magnetoimpedance Effect in Amorphous Nd₄Fe_77.5B_18.5 As Cast Ribbon

Abstract

In the present work, the magnetoimpedance effect is reported in as cast Nd₄Fe_77.5B_18.5 amorphous ribbon. The magnetoimpedance (Z(0)−Z(H))⁄Z(0) is about 16% under H=2.08×10⁴ A·m⁻¹ at 5.1 MHz. The magnetoreactance (X(0)−X(H))⁄X(0) can reach 43.71% under H=2.08×10⁴ A·m⁻¹ at 121 kHz. With increasing ac frequency, the magnetoimpedance (Z(0)−Z(H))⁄Z(0) increases at first, undergoes a peak and finally drops again. The magnetoimpedance (Z(0)−Z(H))⁄Z(0), magnetoresistance (R(0)−R(H))⁄R(0) and magnetoreactance (X(0)−X(H))⁄X(0) intersect at a frequency. Under a lower field H=4.22×10³ A·m⁻¹, the peak frequency f_Z is larger than the intersecting frequency f_i. Under higher fields H≥6.92×10³ A·m⁻¹, the peak frequency f_Z coincides with the intersecting frequency f_i. Both peak frequency f_Z and intersecting frequency f_i increase with increasing dc field.