Effect of a DC transverse magnetic field on the magnetization dynamics in FeCuNbSiB ribbons and derived nanostructured powder cores

The paper aims to give a comprehensive account of DC transverse bias magnetic field influence on the dynamic magnetization processes in Fe73Cu1Nb3Si16B7 soft magnetic ribbons and nanostructured powder cores based on ribbon precursor. These materials were extensively investigated using an approach of impedance spectroscopy from the viewpoint of complex permeability spectra, which offer the indirect insight into magnetization mechanisms and their frequency relaxation. In order to analyze the dynamic nature of domain wall magnetization mechanism, we carried out complex permeability measurements under combined influence of three independent variables, i.e. magnetizing frequency, various driving AC and DC bias magnetic fields. From this ample matrix of results, it has been found that the DC bias smaller than some critical field can increase the real part of complex permeability in the case of as-quenched and annealed ribbon. Nonetheless, the higher fields play a role of additional anisotropy and consequently domain wall damping mechanism. For nanocrystalline compacted powder cores, only the damping influence of DC transverse field was observed. The results are compared in detail and possible mechanisms of domain wall movement damping are proposed and discussed. (C) 2015 Elsevier B.V. All rights reserved.