Method for producing a square loop magnetic media for very high density recording

摘要

A magnetic recording film having high magnetic remanence and unusually good square loop characteristics at thicknesses of between one and five microinches can be deposited directly on non-magnetic electroless nickel from an electroless bath containing cobalt ions, citrate ions, hypophosphite ions, phosphate ions and, if desired, nickel ions. The electroless bath may also contain an ethanolamine, or mixture thereof, as a wetting agent and brightener. The coercive force of the magnetic recording film can be selected to lie between 300 and 1,000 oersteds by adjusting the pH of the bath. Thicker structures with good square loop characteristics and high coercive force can be prepared by the successive plating of two or more magnetic thin films separated by thin films of non- magnetic nickel-phosphorus.