Spatial Distribution Analysis of the Magnetic Domain Structures of Grain-Oriented Electrical Steels Using a Short-Term 2-D Fourier Transform Method

Grain-oriented electrical steels (GOESs), the key components of transformers, should exhibit low energy losses and noise. Hence, the iron loss and magnetostriction (MS), which are determined by the magnetic domain structures of GOESs, should be minimized. Especially, the spacing of the 180 degrees magnetic domain walls and angles, which dominate the magnetic properties of GOESs, should be modulated. In a previous study, a method to quantify the wall spacing and angle of a 180 degrees magnetic domain simultaneously in GOESs based on 2-D Fourier transform (2DFT) was proposed. However, this method is difficult to apply to a large number of grains. In addition, the spatial information before the analysis is eliminated from the post-analysis information. To overcome these limitations, an extension of the 2DFT method is proposed; this extended method can be used to analyze the width and angle of a 180 degrees magnetic domain wall while maintaining the spatial information. The results obtained using the proposed method agree well with the experimental results, demonstrating the effectiveness of the proposed method.