MAGNETOMECHANICAL DAMPING AND DOMAIN STRUCTURES IN GRAIN ORIENTED SILICON STEEL SHEETS

The relation between magnetomechanical damping and magnetic domain structures in highly grain oriented commercial silicon steel sheets has been investigated by the torsion pendulum method of Collette's type as functions of magnetic field, tensile stress and crystallographic orientation. The domain pattern on the specimens is consisted of main 180° domain and a small quantity of supplementary domain structures. The changes in magnetomechanical damping occurring by means of the application of tensile stress to the sheets with different orientations are proportional to the amount of supplementary domains and also magnetic softness. In the specimen with the angle of 55° to the rolling direction, of which the longitudinal axis coincides with [111], the damping capacity was the highest. It was verified, from the results of a coating effect on magnetomechanical damping, that the formation of glass film on the sheet's surface is equivalent to the application of tensile stress of 30-40 kg/cm2.