Excitation Amplitude Dependence of Low Frequency Magneto-impedance of Amorphous Fe73.5Nb3Cu1Si13.5B9 Ribbon

TL;DR

This study investigates how the low-frequency magneto-impedance of amorphous Fe73.5Nb3Cu1Si13.5B9 ribbon depends on excitation amplitude and biasing magnetic fields, revealing nonlinear behavior and significant impedance changes.

Contribution

It provides detailed analysis of excitation amplitude effects on MI in amorphous ferromagnetic ribbons, highlighting the nonlinear dependence and maximum impedance conditions.

Findings

Impedance exhibits nonlinear dependence on excitation amplitude at zero dc field.

Maximum impedance occurs at zero bias field and decreases with increasing Hdc.

Impedance change increases from 45% to 60% as excitation field increases from 14A/m to 140A/m.

Abstract

Magneto-impedance (MI) of soft ferromagnetic materials is a sensitive function of the amplitude and frequency of exciting a.c magnetic field. MI (Z) of amorphous ferromagnetic ribbon of nominal composition Fe73.5Nb3 Cu1 Si13.5 B9 is measured at different excitation currents with frequency ranging from 30kHz to 120KHz The excitation (a.c) and biasing (d.c) magnetic fields Hdc are parallel to ribbon axis. At zero dc fields, Z exhibits non-linear dependence on excitation amplitude whereas at higher d.c fields (9Oe) Z is nearly independent of excitation amplitude. The impedance is maximum at zero bias field and sharply decreases as Hdc increases and almost zero hysterisis has been observed as Hdc is scanned. The maximum relative change of impedance (Z(H)-Z(H=0))/Z(H=0) is found to increase from nearly 45 to 60 percent when the excitation fields goes up from 14A/m to 140A/m. The large MI is associated with screening of electromagnetic field by magnetization induced by exciting ac field.