The influence of deposit composition controlled by changing the relative Fe ion concentration on properties of electroplated nanocrystalline Co-Fe-Cu ternary thin films


Abstract: Ternary Co-Fe-Cu thin films with 78.5-92.4 at.% Co, 4.1-17.9 at.% Fe, and 3.1-3.6 at.% Cu were electroplated at ambient temperature from electrolytes with different relative Fe ion concentrations with respect to the Co ion concentration on the glass substrates coated with indium tin oxide (ITO). It was revealed that the Fe is more easily deposited than Co for all electrolyte conditions. The phase structure of the films changed from a mixture of hcp Co and fcc/hcp Co to a mixture of fcc/hcp Co and bcc Fe and the mean crystallite size diminished with increasing Fe content within the deposits. A shift in the peak position of the fcc/hcp Co phase towards lower 2$\theta $ angles with increasing Fe content within the deposits was observed and the reason for that was discussed. There was also a transition in the surface morphological structure of the films from an acicular-like type structure to a cauliflower-like type structure. The changes that appeared in the surface morphology were related to phase structure, which was affected considerably by the deposit composition.

Keywords: Electrochemical deposition technique, Co-Fe-Cu ternary thin films, phase structure, SEM analyses, deposit composition, anomalous codeposition

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