Magnetic properties of Fe-based soft magnetic nanocrystalline alloys

In this work the magnetic properties of FeCuSiBCuNb soft magnetic nanocrystalline alloys are reviewed. The characteristic magnetic transition associated with the magnetic decoupling of the ferromagnetic grains around the Curie point of the residual amorphous phase is studied through ac inductive techniques (temperature dependence of the magnetic permeability and coercive field). In particular, the study is focused on a Fe68.5Mn5Si13.5B9Cu1Nb3 melt-spun ribbon, where the inclusion of Mn introduces distinctive features in the crystallization and magnetization process of the sample. The main magnetic characteristics of these nanocrystalline systems (i.e. field dependence of the magnetic permeability and nonlinear terms) are analyzed taking into account the particular magnetization process of the exchange coupled ferromagnetic grains around the Curie point of the residual amorphous phase. (C) 2008 Elsevier B.V. All rights reserved.