Dynamic Magnetostatic Energy Correction Based on Domain Area Evolution for Mesoscopic Hysteresis Modeling

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Mesoscopic domain energy models for electrical steel sheets commonly use a constant demagnetizing field.
• This approximation leads to overestimations of magnetostatic energy and distorted simulated hysteresis loops.

Purpose of the Study:

• To introduce a field-dependent coefficient (vH) to accurately scale magnetostatic energy at each magnetization field step.
• To improve the accuracy of mesoscopic domain energy models for electrical steel sheets.

Main Methods:

• A field-dependent coefficient (vH) was developed, calculated from aligned-domain area measurements using magneto-optical Kerr microscopy.
• The coefficient was anchored at the negative coercivity point (-Hc) where macroscopic magnetization vanishes.
• The correction was incorporated into an Assembly Domain Structure Model.

Main Results:

• The refined model significantly reduced coercivity error from 113% to 9-22% and remanence error from 39.9% to 15-17% for grain-oriented steel.
• Consistent vH curves were obtained from measurements in two observation zones, confirming method repeatability.
• The correction was also validated on a second grain-oriented steel grade, showing reduced errors (approx. 23% coercivity, 18% remanence).

Conclusions:

• The proposed field-dependent coefficient accurately accounts for magnetostatic energy variations during magnetization.
• This method enhances the predictive accuracy of mesoscopic models for electrical steel hysteresis loops.
• The technique is broadly applicable across different grades of grain-oriented electrical steel.