Domain models of eddy current loss due to normal magnetization in slightly misoriented

In Goss-oriented SiFe laminations, regions exist with a significant normal magnetization component arising from dip misorientation of the crystallites. It has recently been suggested by Imamura and co-workers that this normal magnetization can make a major contribution
P_{\perp}
to the eddy current losses incurred during cyclic magnetization along the texture axis.
P_{\perp}
is calculated for three distinct domain models of the magnetization process in laminar crystallites with modest dip misorientation. Contrary to the Imamura work,
P_{\perp}
is found to be practically negligible for a simple slab domain structure without closure domains. This is because the normal demagnetizing field restricts normal induction to the neighborhood of the domain walls and ensures that its volume average is practically zero. In a second model monotonic reversal of normal magnetization in closure domain structures is also shown to give rise to rather low normal loss
P_{\perp}
. A third model concerns how closure domains may interact with the major boundaries between slab domains and be swept along with them. Quite substantial losses
P_{\perp}
are predicted if all closure domains in a zone extending a distance rather greater than the sheet thickness either side of the major domain wall are displaced in this way. However, even this mechanism can explain only a small part of the marked increase in eddy loss with dip misorientation reported, and it is concluded that normal flux is probably not primarily responsible.