Magnetoimpedance Effect in Cobalt-Based Amorphous Alloy Irradiated by Nickel and Hydrogen Ions

In this study, we investigate the impact of hydrogen (H) ion and nickel (Ni) ion irradiation with energy of 1.5 MeV and a dose of 1 × 10¹⁵ ions/cm² on the structure and giant magnetoimpedance (GMI) effect for amorphous Co_64.5Fe_4.5Cr₃B₁₀Si₁₈ ribbons. Simulations using SRIM-2008.04 software show that the Ni impurity (H impurity) implanted by irradiation is distributed in a layer about 1 μm (2 μm) thick immediately next to the irradiated surface (near the middle of the thickness) of the ribbon. Ion irradiation with this energy and dose does not alter the amorphous structure, but the DC resistivity is increased by 1.5 times and increased only slightly in the case of irradiation with Ni and H ions, respectively. The GMI ratio and magnetic field sensitivity increase significantly in irradiated samples, reaching 157% and 8.6%/Oe (127% and 6%/Oe) in the case of Ni ion (H ion) irradiation. The skin depth of the Ni (H) ion-irradiated ribbon sample is larger (smaller) than that of the non-irradiated sample, but the transverse permeability \(\left( {\mu_{T} } \right)\) $\left({\mu }_T\right)$ increases. Although ion irradiation reduces the saturation magnetization, as shown by the hysteresis loops and magnetization curves, the increase in \(\mu_{T}\) ${\mu }_T$ supports the enhancement of the GMI effect in the ion-irradiated ribbons. These research results will be beneficial for the development of highly sensitive GMI sensor applications.