Compression Dependence of Magnetization Curves on Iron-Based Soft Magnetic Materials

Magnetic properties of soft magnetic materials under stress are important, however, they have not fully understood. We measured magnetization curves of soft magnetic alloy sheets, electrical steel sheets and nanocrystalline alloys, with positive magnetostriction, under compression. The stress was applied in the same direction of magnetic fields. Magnetization curves have smaller slopes due to anisotropy of magnetoelasticity. The anisotropy energy was estimated from the magnetization curve. And we could obtain a stress dependence of the anisotropy energy; a relation between anisotropy energy and stress was a straight line. The slope of the line correlates magnetostriction values. We devised a magnetic domain model under compression; a magnetization process on the model is a 90 degree magnetic domain wall movement; the relation between anisotropy energy and stress could be formulated. The magnetostriction values estimated from the line slope coincided with experimental ones. Therefore, it can be thought that the magnetization process under compression is mainly 90 degree domain wall movements.