Effect of Eddy Currents on Domain Wall Behavior Configurations, Wall Motion, and Loss for a Domain Model of Cube-On-Edge Material

Abstract

Domain wall motion in single crystals and polycrystalline material has been observed and studied by many physicists and metallurgists under different conditions of excitation. The field has been applied in the rolling direction and in the cross rolling direction and observations made on the surface of the domain wallmotion. In these studies the rate of change of wall motion of necessity must be slow because of the limitations of the procedure for following and photographing the wall motion. It has been recognized that at higher frequencies, the wall tends to bow, but the actual motion has not been defined. The published data under dc excitation conditions, along with the required minimum energy relationship, establishes the boundary conditions that must be met by a domain model for polycrystalline cube-on-edge material. A domain model has been developed which appears to fit these boundary conditions under dc excitation. Analysis of the induced voltage and resulting eddy currents was made on the assumption that the domain wall remain straight and that the velocity was such as to give sinusoidal flux change. The actual flow of eddy currents dictated that the wall must bow. By modifying the domain wall motion to fit the conditions as dictated by the eddy currents, the eddy current losses were calculated and compared with losses measured in present-day material. The variations of magnetizing force with time are also calculated and show reasonable agreement with expected excitation curves versus time.