Magnetostrictivc properties of individual grains in grain-oriented 3% Si-Fe

Magnetostrictive properties of individual grains have been measured by applying a semiconductor strain gauge to every grains in highly oriented 3% Si-Fe sheets with the inorganic surface coating. The magnetostrictive deformation of individual grains depends on the flux density in their locations and also their grain orientations, but it tends to be reduced and equalized with the surface coating. In the specimen with a large variation of an angular parameter φ, the magnetostriction correlates with φ except for very high flux densities. On the contrary, in the specimen with small values of φ (<3-5°), it correlates strongly with the other angular parameter α. At high flux densities, no correlation between magnetostrictions and grain orientations is observed. The unexpected dependence of the magnetostriction on α is accounted for as a result of the volume increase of inner domains possessing the magnetization perpendicular to the rolling direction with the increase of α.