Magnetic properties of rapidly quenched soft magnetic materials

The discovery and large scale investigation of rapidly solidified alloys have brought to light, in the last two decades, a new scenario in basic and applied magnetism. With a range of compositions and microstructural states unavailable to conventional materials, the rapidly quenched alloys have in fact demonstrated unprecedented versatile properties, provided unique opportunities in applications and stirred up the domain of physical theories. In this paper we discuss the basic magnetic features of three classes of rapidly quenched soft magnetic materials: amorphous, nanocrystalline, and high Si alloys. Attention will be focussed on the technically relevant properties correlated with the magnetization process—coercivity, losses, permeability—and their relationship with the structural material properties. The fundamental role of local and macroscopic anisotropies in determining the overall magnetic behavior of these alloys will be highlighted and present trends in the predictive approach to the magnetization process and its dependence on the microstructural parameters will be discussed. Both the static and the dynamic magnetic behaviors will be considered and the loss dependence on the magnetizing frequency will be assessed against modelling.