Controlled electrochemical deposition of magnetostrictive Fe1-xGax alloys

In this study, using steady-state electrochemistry at a rotating disk electrode, a deposition mechanism for giant magnetostrictive Fe1-xGax alloys is proposed in which the formation of an adsorbed monovalent [Fe(1)](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 Fe1-xGax thin films with compositions in the entire range of interest (15%-30% Ga). As-grown Fe80Ga20 thin films were found to have magnetostriction constants of similar to 112 ppm. (C) 2012 Elsevier B.V. All rights reserved.