Controlled electrochemical deposition of magnetostrictive Fe _{1 - X}Ga _x alloys

In this study, using steady-state electrochemistry at a rotating disk electrode, a deposition mechanism for giant magnetostrictive Fe _{1 - x}Ga _x alloys is proposed in which the formation of an adsorbed monovalent [Fe(I)] _ads intermediate is determined to be the rate-determining step. In subsequent steps, this intermediate either gets reduced to iron or catalyzes the reduction of gallium by forming an adsorbed [Ga(III)-Fe(I)] _ads intermediate. In line with the proposed mechanism, it was experimentally shown that the differences in the mass-transport rates of Fe(II) species determined the thin film composition. Therefore, this study has made possible a controllable and reproducible deposition of Fe _{1 - x}Ga _x thin films with compositions in the entire range of interest (15%-30% Ga). As-grown Fe ₈₀Ga ₂₀ thin films were found to have magnetostriction constants of ~ 112 ppm.