Chiral surface formation in magnetoelectrolysis on micro-electrodes

Chiral surface formation in magnetoelectrolysis arises from micro-MHD vortices under vertical MHD flows. Here we report the chiral behaviors of Cu films prepared by magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) on microelectrodes, where the strong influence of the vertical MHD flow on the micro MHD vortices is expected. The MED and MEE of Cu films were conducted on a Pt disc electrode with diameters of 10-100 μm and 3mm at constant currents in a magnetic field of 5T. The chiral sign of the MED films at the 3-mm-electrodes depended on the polarity of the magnetic field. On the contrary, the MED films at the 100-μm-electrodes exhibited chiral symmetry breaking for the polarity of the magnetic field. Chiral behavior disappeared in the films at the 10-μm electrodes, suggesting the suppression of the micro-MHD vortices. Similar results were obtained in the MEE processes.