Electrodeposition of Ni–Co–Cu/Cu multilayers

It has long been known that a concentration gradient can develop in electrodeposits along the growth direction as a result of the combined impact of anomalous codeposition and mass trasnport limitation of the reactants. It is shown in the present paper that this composition change in electrodeposited Co–Ni–Cu/Cu multilayers can be verified by secondary neutral mass spectrometry (SNMS). Various electrodeposited samples have been analyzed and the resulting composition profiles have been compared to the calculation based on the non-destructive analysis of the overall composition. The change of the Co:Ni ratio in the magnetic layer along the growth direction has been verified. A calculation method has been proposed by which the local composition of the magnetic layer can be estimated from the thickness dependence of the overall multilayer composition. It has also been shown that the deviation of the experimental depth profile data from the estimation based on the variation of the total composition with the Co–Ni–Cu layer thickness can be ascribed to the roughness increase during the sputtering in the SNMS instrument.