Frequency-Induced Bulk Magnetic Domain-Wall Freezing Visualized by Neutron Dark-Field Imaging

Abstract

The core of a power transformer is subject to $t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}e-v\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}y\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}g$ magnetic fields. In this study the authors visualize in detail the interplay between the frequency and amplitude of magnetic excitation, to study the frequency-induced freezing of bulk magnetic domain walls in electrical steel. A basic understanding of this freezing is needed to develop macromagnetic models, leading to transformers with improved performance and efficiency.