How to obtain structured metal deposits from diamagnetic ions in magnetic gradient fields?

Electrodeposition of Bi in magnetic gradient fields was performed from two different electrolytes. The first electrolyte contained only diamagnetic Bi3+-ions; the second one additionally contained electrochemically inert paramagnetic Mn2+-ions. While homogeneous Bi deposits were obtained from the former, structured Bi layers were derived from the latter. The structured deposits show an inverse correlation between deposit thickness and superimposed magnetic field gradient. Minima of film thickness are observed in regions of maximum magnetic gradients. This demonstration of magneto-electrochemical structuring by deposition of diamagnetic ions is discussed considering the acting magnetic forces. Several possibilities explaining the structuring mechanism are presented.

► Electrodeposition of Bi was performed in magnetic gradient fields.
► Homogeneous layers resulted when the electrolyte only contained diamagnetic Bi3+.
► Addition of inert paramagnetic Mn2+ to the electrolyte yielded structured Bi deposits.
► Minima of deposit thickness were found at maximum magnetic gradients.
► Influences of magnetic forces were discussed and possible structuring mechanisms were proposed.