Domain wall drift due to nucleation during cyclic magnetization

A detailed investigation was made, using Kerr effect cinematography, of the domain wall motion during cyclic magnetization in single crystals of a 3% Si-Fe alloy. At low levels of peak magnetic induction and magnetization frequency the midpoint of each slab-like domain remains stationary. With the onset of domain nucleation, at higher inductions and frequencies, as previously observed, the existing domain structure is found to drift to accommodate the new domains. Such drift contributes to additional eddy-current losses during the cycle. These losses can be approximated for simple models of the drift process by making use of eddy current losses associated with a domain structure.