Frequency dependence of iron losses in 4-percent Si-Fe single crystal with

Losses under ac field excitation have been measured as a function of frequency and induction for a (100) [OOl] single crystal of 4-percent Si-Fe and, simultaneously, the stroboscopic observation of dynamic domain structure has been made using the Kerr magnetooptic effect. From the results of iron loss measurement, it has been confirmed that, in a (100) [001] specimen, for a range of flux densities the loss per cycle W/ƒ versus ƒ curves are not linear in the measured range of frequencies from 1 to 80 Hz. At low flux densities, the curves approximate to straight lines in the low-frequency range and their slopes are in excellent agreement with the theoretical slopes predicted by the model of Pry and Bean. It has now been shown that, with increasing frequency, W/ƒ curves become nonlinear and the eddy-current loss components of the measured loss agree fairly well with theoretical values based on them odel of Lee, in which the skin effect is considered.