Electrodeposited CoPt films from a deep eutectic solvent

CoPt magnetic alloy has been successfully electrodeposited for the first time in a choline chloride/urea based deep eutectic solvent (DES) on glass/ITO substrate. A vitreous carbon substrate has been used to test and analyse the deposition processes of both platinum and platinum–cobalt systems in the DES. The potential range at which CoPt alloy with variable Pt:Co ratio can be prepared was established. Both grey and bright alloy deposits, showing nodular morphology and uniformly distributed on the substrate were obtained. The composition was homogeneous in the deposit and absence of contamination due to DES solvent was demonstrated. The crystalline structure of the CoPt deposits prepared in the 50 to 85 wt.% Pt range evolved from Co hcp to Pt fcc distorted phases. Coercivities around 1900 Oe were measured for deposits with around 54 wt.% Pt.

► Magnetic CoPt electrodeposits, free of contaminants, were obtained in a DES solvent.
► Co:Pt ratio was tailored by the applied potential.
► Coercivity of 1900 Oe has been achieved for deposits of around 54 wt.% Pt.