Fitting of giant magnetoimpedance curves using the complex method in optimization techniques

Abstract The giant magnetoimpedance (GMI) effect is characterized by substantial variations in both the real and imaginary components of the impedance when subjected to an alternating current in the presence of a static magnetic field. In quasistatic models, the GMI profile can be effectively delineated by the changes in transverse permeability in response to variations in the external magnetic field. Building on this, the magnetic anisotropy field and anisotropy angle for specific magnetic phases can be determined by fitting the experimental data points. The dual magnetic phase structure of the CoP/NiCoP/Cu composite wire results in a four-peak profile in its GMI curves, making it suitable as a target curve for fitting. By preprocessing the GMI curves and applying the Complex Method within optimization techniques through multiple iterations, the theoretical target curve is ultimately obtained, along with the extraction of the physical parameters embedded within it. This approach presents a novel solution to the multi-parameter curve fitting.