Large magnetostriction in Fe-Ga rapid-solidified alloy

Rapid-solidification method was applied to make the Fe-15 at%Ga ribbon whose thickness was about 100 μm with improvement of ductility. The Fe-15 at%Ga ribbon sample showed a very large magnetostriction of ε_max = -400 × 10^-6 in comparison with ε_max = - 40 × 10^-6 for the conventionally melt-worked bulk material at applied magnetic field, 955 kA/m. In the bulk material with random crystal orientation, the dependence of magnetostriction on magnetization direction (θ) to the surface of ribbon was scarcely recognized. On the contrary, in rapid-solidified ribbon, that dependence was extraordinarily enhanced and large magnetostriction was obtained in the thickness direction of ribbon (θ≒90°) where coercive force showed the maximum value. Based on these experimental results, it is considered that the large magnetostriction is strongly correlated with special metallic microstructures in the rapid-solidified Fe-15 at%Ga ribbon with very strong magnetic anisotropy. Fe-Ga rapid-solidified ribbon has the promising possibility as a new magnetostrictive material as it has large magnetostriction, ductility and very small magnetostriction hysteresis.