High-Frequency Magnetoimpedance Effect in Five-Layer Nanostructured Thin Film: Magnetostatic Coupling in Symmetric Structure

In the field of high-frequency magnetic impedance (MI) research, accurately describing the MI effect in multilayer nanostructured thin films remains a challenging task. A model to accurately describe high-frequency magnetoimpedance in the FeNi/Co/Cu/Co/FeNi five-layer nanostructured thin film is developed. The GMI response was obtained through the simultaneous solution of Maxwell’s equations and the Landau-Lifshitz equation. Through the induction of an effective bias field in the soft magnetic layer, the magnetostatic coupling between the soft and hard magnetic layers is taken into account. At frequencies up to GHz magnitude, symmetrically structured nanofilms are capable of obtaining a greater MI ratio through magnetic coupling. Furthermore, we demonstrate that modifying film properties and manipulating the bias field can lead to improved sensing performance. This study not only fills the gap in the theoretical model of five-layer nanostructured symmetrical films but also provides a theoretical foundation for the design and optimization of high-performance magnetic sensors operating at high frequencies. The findings presented in this paper hold potential to advance the development of high-frequency magnetic impedance sensors.