Multi-layer amorphous magneto optical recording medium

A magneto optical recording medium comprising:

• A. a magnetizable amorphous film having a magnetic anisotropy perpendicular to the film surface, said film being characterized by having:
• (i) a multiplicity of magnetic domains substantially all of which have a domain size of less than 500 angstroms, and (ii) a thickness greater than about 5 nanometers;
• B. an intermediate layer covering one side of the film of part A. and comprising a transparent dielectric characterized by a thickness of about 30 to 200 nanometers, and an index of refraction greater than about 1.2;
• C. an anti-reflective layer covering the side of the magnetizable amorphous film of part A opposite the layer of part B, said anti-reflective layer being characterized by a thickness of about 30 to 200 nanometers and an index of refraction greater than about 1.2;
• D. a substrate located on the side of either the layer of part B or part C opposite the film of part A;
• E. a reflective surface which is either a polished surface of the substrate or a separate reflecting layer of reflective metal, said separate reflecting layer being located on the side of the layer of part B opposite the film of part A;
• the relative thicknesses of the intermediate layer, the magnetizable amorphous film and the anti-reflective layer being selected to yield a magneto optic angle of rotation exceeding that of the recording medium without either the intermediate or anti-reflective layer;
• and said recording medium being characterized by a carrier-to-noise ratio of at least 47 decibels measured in a 30 kilohertz band width.

A magneto optical recording medium comprising:

• A. a magnetizable amorphous film having a magnetic anisotropy perpendicular to the film surface, said film being characterized by having:
• (i) a multiplicity of magnetic domains substantially all of which have a domain size of less than 500 angstroms, and (ii) a thickness greater than about 5 nanometers;
• B. a transparent dielectric layer covering one side of the film of part A. and characterized by a thickness of about 30 to 200 nanometers, and an index of refraction greater than about 1.2, said transparent dielectric layer being located on either side of the magnetizable amorphous film;
• C. a reflecting layer covering a side of either the film or part A. or the transparent dielectric layer of part B.;
• and
• D. a substrate comprising a transparent protective covering material, covering the side of the medium opposite the reflecting layer;
• the relative thicknesses of the magnetizable amorphous film and the transparent dielectric layer being selected to yield a magneto optic angle of rotation exceeding that of the same recording medium without the dielectric layer;
• said recording medium being characterized by a carrier-to-noise ratio of at least 47 decibels measured in a 30 kilohertz band width.