Influence of stress on magneto-impedance in Co71-xFexCr7Si8B14 (x = 0, 2) amorphous ribbons

TL;DR

This study investigates how applied stress influences the magneto-impedance in Co-rich amorphous ribbons, revealing high sensitivity and significant impedance changes under stress, with potential applications in stress sensing.

Contribution

It provides systematic measurements of stress-impedance effects in Co71-xFexCr7Si8B14 ribbons across frequencies and stresses, highlighting the impact of stress on magneto-impedance and magnetization.

Findings

Impedance varies significantly with applied tensile stress, up to 80% at low frequency.

Maximum magneto-impedance ratio observed is 99% at low magnetic fields.

Stress application decreases impedance and broadens MI curves, confirming negative magnetostriction.

Abstract

Systematic measurements of stress-impedance (SI) have been carried out using Co-rich amorphous ribbons of nominal composition Co71-xFexCr7Si8B14 (x = 0, 2) at various excitation frequencies and bias fields and at room temperature. The impedance, Z for both the samples was found to be very sensitive functions of applied tensile stresses (up to 100MPa) exhibiting a maximum SI ratio as much as 80% at low frequency ~ 0.1MHz. The nature of variation of SI changes with the excitation frequency especially at higher frequencies in MHz region where it exhibits a peak. Magnetization measurements were also performed to observe the effects of applied stresses and magnetization decreased with the application of stress confirming the negative magnetostriction co-efficient of both the samples. Both the samples exhibited negative magneto-impedance (MI) when the variation of Z is observed with the applied bias magnetic field, H. The impedance as functions of applied magnetic field, Z(H), decreases with the application of stress thus making the MI curves broader. Maximum MI ratio as large as 99% has been observed for both the samples at low fields ~ 27Oe.