SURFACE-MORPHOLOGY OBSERVATION OF SILICON STEEL SHEETS BY SCANNING TUNNELING MICROSCOPE

Scanning tunneling microscope (STM) has been applied to the investigat ion of surface morphology of silicon steel sheets. A polished specimen was annealed in a vacuUM of 10(-4) Pa at 1300-degrees-C for 10 min. T he detailed observations reveal that fine facet structure is formed ne ar (001) of the alpha-Fe grains, and that the terrace width and the st ep height of the facet are determined by the misorientation angle of t he grains from the [001] orientation. These results and the observed m inimum step height of 0.5 nm of the terrace suggest that the (001) sur face of the silicon steel sheets can be covered with a this iron oxide film with possible orientation relationship of alpha-Fe(001)//FeO(001 ) or alpha-Fe(001)//Fe3O4(001) and alpha-Fe[100]//FeO[110] or alpha-Fe [100]//Fe3O4[110]. The change of facet structures due to lowering anne aling temperature are also discussed.