A method is disclosed for defining discrete magnetic and non-magnetic regions on the magnetic film layer of a storage media substrate. The method applies anodic oxidation of a cobalt-containing magnetic film layer to remove cobalt, followed by controlled deposition of a non-magnetic matrix into the regions where the cobalt has been removed. Deposition may either be electrodeposition, collimated vacuum deposition, or other methods depending upon the composition of the non-magnetic matrix being deposited. The method may be performed in a single electrochemical cell.