Dynamic domain wall movement of surface scratched silicon steels

The relationship between the magnetic domain configuration and the groove dimension on grain-oriented 3% Si-Fe sheets was examined in the vicinity of the grooves using a scanning electron microscope. The grooves were formed on the sheet surface by a chemical scratching technique in order to refine the magnetic domains to reduce the eddy current loss. The eddy current loss considerably increased when the groove depth exceeded 20 μm in sheets of 62-76-μm thickness. The optimum groove dimension for decreasing the loss was determined by observing the dynamic domain wall movement at 50 Hz. After the optimum domain refining, the iron loss of the 32-μm thick sheet became W13/50=0.13 W/kg and W17/50=0.21W/kg. The former is lower than the value determined for an Fe-based amorphous sheet