Electrochemical preparation and magnetic properties of Co–Cu nanometric granular alloy films

detailed electrodeposition of Co–Cu nanometric granular alloy films in citrate solution has been performed based on a galvanostatic technique. Electrochemical behaviour of the bath solution containing both Co^2+ and Cu^2+ was investigated by linear sweep voltammetry. Cathodic polarization curves indicated that high quality Co–Cu nanometric granular alloy films can be obtained at room temperature with a pH of 6 and current density equal to or more negative than - 1.0 mA cm^-2 . Magnetic properties of the films were measured at room temperature by the physical property measurement system. Magnetization curves of the as-prepared Co–Cu nanometric granular alloy films displayed superparamagnetism (SPM). However, after annealing at 450^∘C for 1 h, magnetic property of the films changed from SPM to ferromagnetism. Meanwhile, the annealed Co–Cu nanometric granular alloy films showed an increase in saturation magnetization with the increase of the current density.