The electrodeposition behaviors and magnetic properties of Ni-Co films

Ni-Co films with different compositions and microstructures were produced on ITO glasses by electrodeposition from sulphate bath at 25 °C. Cyclic voltammograms give a result that the increase in the Co2+ concentration displaces Ni-Co alloy oxidation peaks to negative potential with high Co current distributions. It is observed that the content of cobalt in the films increases from 22.42% to 56.09% as the molar ratio of CoSO4/NiSO4 varying from 0.015/0.085 to 0.045/0.055 in electrolyte. XRD patterns reveal that the structure of the films strongly depends on the Co content in the deposited films. The saturation magnetization (Ms) moves up from 144.84 kA m−1 to 342.35 kA m−1 and coercivity (Hc) falls from 15.27 kA m−1 to 7.27 kA m−1 with the heat treatment temperature increasing from 25 °C to 450 °C. The saturation magnetization (Ms) and coercivity (Hc) move up from 340.97 kA m−1 and 7.98 kA m−1 to 971.58 kA m−1 and 18.62 kA m−1 with the Co content increasing from 22.42% to 56.09% after annealing at 450.

Research highlights▶ The ITO glasses were used as the substrate in the field of Ni-Co film. ▶ Higher Co2+ concentration causes a negative shift of the oxidation peak. ▶ The oxidation currents increase with the increase of Co2+ concentration. ▶ Structures of the heated films were specifically discussed.