Domain observation is indispensable for studying the loss mechanism of grain-oriented 3% silicon-iron. The losses of this material are affected considerably by the conditions of steel surface, especially surface coating. The direct observation of domain patterns without surface polishing or removing of surface coating is necessary for studying the real magnetization process of this material
The domain observation method using SEM with a backscattered electron image is useful for studying the behavior of grain-oriented 3% silicon-iron, especially at high accelerating voltage where the coating can be penetrated to reveal the magnetic domain structure beneath. Dynamic domain patterns can be observed by SEM, also.