Influence of microwave annealing on GMI response and magnetization of an amorphous Fe73.5Nb3Cu1Si13.5B9 ribbon

TL;DR

This study investigates how microwave annealing affects the magneto-impedance response and magnetic properties of an amorphous Fe-based ribbon, revealing reduced impedance response and increased magnetic hardness after treatment.

Contribution

It provides new insights into the effects of microwave annealing on magneto-impedance and surface crystallization in amorphous Fe-based ribbons.

Findings

Magneto-impedance response is significantly reduced after microwave annealing.

Surface crystallization occurs as shown by XRD measurements.

Magnetic hardness increases and initial susceptibility decreases by two orders of magnitude.

Abstract

The resistive and reactive components of magneto-impedance was studied for the as-quenched and microwave annealed amorphous Fe73.5Nb3Cu1Si13.5B9 ribbon as a function of biasing d.c magnetic fields (-60 to +60 Oe) and excitation frequencies (0.1, 1, 10 and 20MHz). The magneto-impedance (both components) response was much reduced for the microwave annealed ribbon and the changes were more discernable at higher excitation frequencies. The imaginary component of magneto-impedance showed maxima at finite (non-zero) d.c magnetic fields for both the as-quenched and microwave annealed ribbons. Magnetization measurements performed for both the as-quenched and microwave annealed ribbons revealed the magnetic hardness of the latter. The initial susceptibility decreases by two orders of magnitude for the microwave-annealed ribbon. XRD measurements indicated the transformation of the surface of the ribbon from the amorphous state to the crystalline one.