Abstract: A method for producing a continuous thin film magnetic medium by electrochemical plating deposition, useful for perpendicular recording. The plated medium comprises a substrate upon which is deposited a thin magnetic layer consisting of acicular shaped crystalline particles with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the particle acicula and the longitudinal axis of the acicular particles oriented substantially normal to the plane of said magnetic layer. The method comprises the steps of providing an electrochemical plating bath solution containing a salt solution of the magnetic elemental component or alloy thereof, e.g., Co salt solution, the bath having a predetermined ion concentration and electrodepositing the elemental component or alloy thereof on the substrate while maintaining the maximum pH value of the salt solution at a point before the precipitation of a secondary precipitate, e.g., Co(OH).sub.

Abstract: A method of electrochemical post treatment to a continuous thin film magnetic medium designed for perpendicular recording comprising a substrate upon which is deposited a thin magnetic layer comprising acicular shaped crystalline magnetic particles with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the particle acicula and the longitudinal axis of the acicular particles oriented substantially normal to the plane of said magnetic layer, the post treatment effectively increasing the separation between magnetic particles and thereby increasing their coercivity while decreasing their demagnetization field of the film. The method comprises the step of utilizing enhanced grain boundary reaction at the interganular boundary of the acicular particles to achieve particle separation effectively either by electrochemical charging by cathodic action in solution or electrochemical etching by anodic action in solution.