Magneto-impedance effect in amorphous wires

TLDR

Recent experiments have discovered a giant magneto‑impedance effect in FeCoSiB amorphous wires, with up to 60 % change in high‑frequency voltage under a dc magnetic field, analogous to giant magnetoresistance. The study examines this phenomenon through the lens of AC complex resistance or impedance. The effect arises from the skin effect combined with a strong field dependence of circumferential magnetic permeability due to circular domain wall movements. Theoretical predictions match existing experimental data satisfactorily.

Abstract

Recent experiments have discovered a giant magneto-impedance (MI) effect in FeCoSiB amorphous wires. This effect includes a sensitive change (as much as 60%) in a high frequency wire voltage by an applied dc magnetic field and is thus a high frequency analog of giant magnetoresistance. We consider this phenomenon in terms of ac complex resistance or impedance. The giant MI effect is demonstrated to arise from a combination of a skin effect and a strong field dependence of the circumferential magnetic permeability associated with circular domain wall movements. The theoretical results agree satisfactorily with the existing experimental data.