Anomalous eddy current loss in amorphous magnetic thin sheets and its improvement

Soft magnetic properties of amorphous metals are interesting for application in transformers and other devices. So far, annealing in a field applied parallel to the amorphous ribbon axis was necessary to obtain the desirable magnetic properties. However, the amorphous cores made by this annealing method exhibit large eddy current losses. In order to reduce such large anomalous losses, we have improved the field annealing method, by applying the field oblique to the ribbon axis. In Fe-rich amorphous alloys, the core losses have been reduced by about 30-40 % by this method. Relation between the core losses and the magnetic domain structure has been investigated by comparing with the theory of Pry and Bean.