Giant magnetoimpedance: new electrochemical option to monitor surface effects?

TL;DR

This study explores a new electrochemical method using giant magnetoimpedance (MI) sensors to monitor surface effects caused by biofluids, aiming to differentiate surface modifications from sensing signals.

Contribution

It introduces a robust MI sensor prototype capable of separating chemical surface modifications from sensing processes, demonstrating its potential as an electrochemical surface probing tool.

Findings

MI variation correlates with surface magnetic anisotropy changes

Sensor effectively distinguishes surface modifications in biofluids

Electrochemical MI sensing can probe electric features of magnetic electrodes

Abstract

Magnetoimpedance, MI, change due to surface modification of the sensitive element caused by biofluids was studied with the aim of creating a robust sensor capable of separating the chemical surface modification from the sensing process. A MI sensor prototype with an as-quenched FeCoSiB amorphous ribbon sensitive element was designed and calibrated for a frequency range of 0.5 to 10 MHz at an intensity of the current of 60 mA. Measurements as a function of the exposure time were made, first, in a regime where chemical surface modification and sensing were separated and then, in a regime where they were not separated (in a bath for fluids). The MI variation was explained by the change of the surface magnetic anisotropy. It was shown that the magnetoimpedance effect can be successfully employed as a new electrochemical option to probe the electric features of surface-modified magnetic electrodes when the biofluid, the material of the sensitive element, and the detection conditions are properly selected and synergetically adjusted.