Magnetic Domain Motion and Magnetostriction in the Fe–Ga Sheets

The magnetic domain motion with varying magnetic field is investigated by magneto-optic Kerr microscopy on a slightly Goss misoriented Fe-Ga rolled sheet, and a close relationship between the magnetostriction and the domain motion is reported during the magnetization process. Along the rolling direction (RD), a high magnetostriction value λ_// of 281 ppm is observed under no prestress for the sheet. The magnetic domains on the ~12° misoriented Fe-Ga (110) surface appear in the lancet shape and align as lancet comb structures. The lancet domain motion on the surface well explains the magnetostrictive performance λ_// with the consideration of 90° domains within the lancet structure. The rapid increase of magnetostriction is attributed to the quick motion of 90° domains within the lancet structure under the field below 70~100 Oe. Under the higher magnetic field, these lancet domains gradually disappear with the field increasing, accompanied with the approach to the saturation magnetostriction along the RD.