Giant magneto-impedance effect in CoP/Cu bilayers meander-like sensing elements

Abstract

The giant magnetoimpedance (GMI) effect, characterized by large variations in the electrical impedance of soft magnetic materials under weak magnetic fields, arises from changes in magnetic permeability, which influence the skin depth of high-frequency currents and is strongly affected by the dynamic behavior of magnetic domains. Due to its high sensitivity, the GMI effect has been widely explored for magnetic field sensing applications. In this study, three rectangular Co90P10/Cu meander-like GMI-based sensing elements were manufactured using printed circuit board assembly (PCBA) and electrodeposition techniques. The GMI response of three Co90P10 meanders with thicknesses of 4.2, 9.8, and 15.0 μm were investigated in a frequency (f) range of 0.1 MHz–1.8 GHz for in-plane and perpendicular applied magnetic fields. The thickest CoP meander had the overall best results, presenting a GMI of 21% at 5 MHz, and a peak of 55.4% at 1.8 GHZ corresponding to an impedance variation of 66.3 Ω for H≈58.8 Oe. The highest sensitivity of max=4.8Ω/Oe was achieved by the thinnest sample at 1.0 GHz for a longitudinal field. These devices demonstrated high sensitivity, robustness, and broadband performance. Importantly, the use of commercially available copper rails instead of high-purity copper, without compromising the GMI response, supports scalable and low-cost production. These results highlight a novel integration of Co90P10 meandered GMI sensors into PCB platforms and open promising avenues for real-world applications in wireless communications, contactless current sensing, and biomedical diagnostics, advancing the practical deployment of GMI technologies in applied physics and engineering systems.