Abstract: A method and apparatus for storing data and for reducing the magnetic moment of a ferromagnetic material is provided incorporating a magnetic film, a blanket or patterned film of germanium adjacent the magnetic film, and means for heating the interface of the two films to at least 200.degree. C. to permit diffusion of the germanium into the magnetic film and thereby reduce the magnetic moment. The invention overcomes the problem of forming recording tracks on storage media and patterning magnetic films for inductive and magneto resistive heads for retrieving data from moving storage media.