Tailoring magnetostriction and magnetic domains of <100>-oriented Fe80Ga16Al4 alloy by magnetic field annealing

Abstract

Magnetic field annealing (MFA) was used to tailor the magnetostriction and magnetic domains of Fe80Ga16Al4 alloy, and the relationship between the two characteristics was studied. The -oriented alloy was prepared by the directional solidification technique and annealed for 20 min at 700 °C in a magnetic field of 250 mT along a direction 45° to the orientation, followed by furnace cooling in the same magnetic field. The magnetostriction along the length direction (λ∥), the width direction ( $$\lambda_{ \bot }$$ ) and the saturation magnetostriction (λs) was changed from λ∥ = 208 × 10−6 and $$\lambda_{ \bot }$$ = − 16 × 10−6 of the initial alloy to λ∥ ≈ − $$\lambda_{ \bot }$$ ≈ ½ λs ≈ 112 × 10−6 after MFA. The magnetic domain structure, which mainly refers to the number, size, and direction of the domains, was tailored and rearranged by MFA. This rearrangement of the magnetic domain structure resulted in a shift of magnetostrictive properties parallel and perpendicular to the orientation for the Fe80Ga16Al4 alloy. This magnetic field annealing method can aid understanding of the relationship between the microscopic magnetic domains and the macroscopic magnetostrictive properties. It can also aid in further tailoring better magnetostrictive properties within magnetostrictive materials to meet the requirements of different application conditions.