Effects of magnetic field annealing on magnetic properties in ultrafine crystalline Fe-Cu-Nb-Si-B alloys

The relation between magnetic field annealing and magnetic properties in Fe-based alloys called FINEMET, composed of an ultrafine grain structure, have been studied. High-remanence-ratio B-H curves and flat B-H curves can be obtained by longitudinal-field and transverse-field annealing, respectively. The values of core loss and relative permeability of FINEMET alloys annealed in a magnetic field are similar to those of Co-based alloys, and they show excellent soft magnetic properties in the high-frequency range. The alloys annealed in longitudinal fields are suitable for saturable reactors and high-frequency transformers, and those annealed in transverse fields are suitable for choke coils.<
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