Magnetic properties of grain-oriented silicon iron. Part 4: Relationship of domain spacing, grain size, sheet thickness and power loss

Measurements of total power loss and domain spacing have been made on individual grains of varying size in grain-oriented silicon iron at various frequencies (20¿150 Hz) at 1.5 Wb/m2, using recently developed experimental techniques, Minimum total power loss occurs in 0.013 in (0.033cm) thick material at a grain size of about 0.7cm. In the grains studied, the walls followed a simple bar arrangement and moved smoothly without jerks, and repetitively, over approximately the same distances, the equilibrium wall spacing was independent of the frequency. The relevance of these results to explanations of the anomalous loss based on domain-wall models is discussed.