Dynamic magnetic studies using impedance spectra

In this work, a method to study the dynamic properties of magnetic materials through the impedance spectra is presented. Fittings of the μ vs. f curves extracted from the impedance spectra were made. In this way, we are able to obtain the main quantities describing the dynamic properties of a magnetic material, namely the domain wall and rotation contributions to the overall permeability, as well as the relaxation frequencies associated with the wall motion. The method was applied to samples of (1 1 0)[0 0 1]FeSi 3% with different angles between the easy axis and the magnetization direction. The well-known details of the domain structure evolution of this material were used to interpret the μ× f× H DC curves.