Investigation of ferromagnetic layer dissolution characteristics during pulse electrodeposition of FeCoNiCu/Cu multilayers

Minimization of interface roughness of electrodeposited metallic multilayers with nanometer thick sublayers during pulse electrolysis largely depends on the choice of potential pairs and electrolyte. In this study, a systematic effort has been made to identify the different origins of less noble ferromagnetic (FM) layer dissolution during two pulse potentiostatic electrochemical deposition (ECD) of FeCoNiCu/Cu multilayers and its subsequent minimization. Detailed investigations by employing cyclic voltammetry and chronoamperometry, it was established that the FM layer dissolution not only depends on copper layer discharge potential (ECu) but also on FM layer discharge potential (EFM) and Cu2+ concentrations. Both the cell capacitance effect and galvanic displacement reactions are accountable for corrosion of FM layer. It was found that potentials, EFM = −2.3 V vs. SCE and ECu = −0.6 vs. SCE are the optimum pair for growth of FeCoNiCu/Cu multilayers with minimum dissolution of FM layer.