# Domain Structure Transformation and Impedance Tuning in Partially Nanocrystallized Fe-Based Microwires

## TL;DR

This paper shows how partial nanocrystallization in Fe-based microwires enhances their magnetic and electrical properties, making them better for high-sensitivity sensors.

## Contribution

The study reveals a strong coupling between surface nanostructuring, domain configuration, and magnetoimpedance behavior in Fe-based microwires.

## Key findings

- Partial nanocrystallization increases giant magnetoimpedance by up to 150% in Fe-based microwires.
- Magnetic domain structures transform from inclined/zigzag to ring configurations with radial magnetization.
- Domain transformation occurs in the same magnetic field range as the maximum impedance response.

## Abstract

Fe-based amorphous microwires were studied to examine the effect of partial surface nanocrystallization on their magnetic and electrical properties. Controlled annealing was used to induce nanocrystallization within the surface layer of the metallic core. The giant magnetoimpedance (GMI) was found to increase up to 150% compared to the as-cast microwires, which correlates with variations in the electromagnetic skin depth. Magnetic force microscopy (MFM) revealed a pronounced transformation of the magnetic domain structure: inclined and zigzag domains evolved into a ring domain configuration with radially oriented magnetization. This transformation of the domain structure occurred within the same magnetic field range where the maximum impedance response was observed. These results show a strong coupling between surface nanostructuring, domain configuration, and magnetoimpedance behavior, providing insights for optimizing Fe-based microwires for use in high-sensitivity magnetic and mechanical sensors.