Electrodeposition of CoNiP films with modulated magnetic behaviour

The electrodeposition technique has allowed the preparation of micrometre scale films of cobalt– nickel–phosphorus with different magnetic properties which are a function of the electrolytic bath composition, the current density applied and the bath temperature. The deposits were obtained from solutions containing nickel (II) and cobalt (II) sulphamates and sodium hypophosphite as a source of phosphorus. From a new bath formulation, uniform and fine grained ternary deposits were obtained using a minimum amount of wetting agents and stress relieving additives. Soft magnetic layers were obtained when deposits were grown at low deposition rates (temperature of 30uC and low current densities). Increases in both bath temperature and applied current density led to deposits losing their soft magnetic behaviour.