Impact of substrate on the formation mechanism of electrodeposited Co–Ni thin films: a comprehensive study of structural, morphological, and magnetic properties

In this work, we investigated the effect of substrate on the structural, morphological, and magnetic properties of electrodeposited CoNi thin films from a chloride bath. Three samples of CoNi films were deposited at room temperature onto different substrates: FTO, ITO, and Cu. Electrochemical studies were performed using cyclic voltammetry experiments. Energy-dispersive X-ray spectroscopy (EDX) showed that all the samples had a cobalt content of more than 80%. X-ray diffraction (XRD) spectra revealed that the films deposited on Cu had a face-centered cubic (FCC) phase, while those deposited on ITO and FTO had a mixture of hexagonal close-packed (HCP) and FCC phases. The lattice parameter (a) and crystallite size (D) were strongly dependent on the substrate. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe the morphology of the films. All the samples had a granular morphology with spherical grains, but the roughness and surface distribution varied with the substrate. The magnetic properties of the films, such as coercivity (Hc) and squareness (S), were investigated using a vibrating sample magnetometer (VSM). The results showed that Hc and S were both affected by the substrate and the film composition. Overall, our results showed that the substrate had a significant effect on the structural, morphological, and magnetic properties of electrodeposited CoNi thin films. These findings could be used to design and optimize CoNi thin films for specific applications.