| 摘要 |
PURPOSE:To obtain a vertical magnetic recording medium of high characteristics which enables the reduction in recording current, has a large S/N and is free from spike noise by providing a thin film having high magnetic permeability, a film of a antiferromagnetic material, a film having high magnetic permeability and a vertically magnetized film in this order on a substrate. CONSTITUTION:A thin film having high magnetic permeability such as Ni80Fe20, a thin film of an anti-ferromagnetic material such as Fe50Mn50, and a thin film having high magnetic permeability such as Co80Mo9.5Zr10.5 are formed successively on an annular non-magnetic substrate, whereafter a vertically magnetized film is formed of an alloy such as Co80Cr20 thereon to 0.03-0.3mu thickness. Since the thin film of the anti-ferromagnetic material is provided between the thin films having high magnetic permeability, the generation of spike noise is eliminated and the excellent vertical magnetic recording medium having a high S/N with the decreased current necessary for recording is obtd. If an amorphous metallic film is used for the film having high magnetic permeability on the antiferromagnetic layer, better performance is obtd. The higher S/N is obtainable by applying a magnetic field in the transverse direction of tracks in the stage of forming the respective magnetic layers. The much higher S/N is obtainable if the entire part is heat treated in a vacuum or inert gas or reducing gas kept a 350- 550 deg.C after the formation of the vertically magnetized film by using both upper and lower film having high magnetic permeability of which the Curie point is higher than the heat treatment temp. and the anti-magnetic material film of which the Neel temp. is higher than said heat treatment temp. |
