Strain-induced magnetic degradation in shearing FeSiB nanocrystalline thin foils analyzed by magneto-optical Kerr effect

FeSiB nanocrystalline thin foil is a promising material for magnetic cores. However, the shearing process causes magnetic degradation owing to the strain-hardening layer at a depth of approximately 100 μm from the sheared surface of the core teeth. Reducing the strain-hardening effect while considering the local magnetic flux density is a challenging task. This study utilized a ductile–brittle transition regime of the nanocrystalline to reduce the strain-hardening effect and was validated using a precision shearing test. A magneto-optical Kerr effect-based method was proposed to quantitatively evaluate the local flux density, providing novel insights for understanding the shearing-induced magnetic degradation.