The present application provides a preparation method of a hydrogenated composite film and an optical filter, and relates to the field of optical film filter technologies. The preparation method includes: introducing inert gas and hydrogen into a reaction chamber, and bombarding at least two materials in the reaction chamber and the introduced hydrogen using plasma formed by the inert gas, such that the at least two materials are sputtered onto a substrate and react with hydrogen ions generated by the hydrogen to form a hydrogenated composite film layer. The hydrogenated composite film layer includes at least two materials which are co-sputtered onto the same substrate using the sputtering technology to obtain a required material performance, so as to obtain the hydrogenated composite film layer with a refractive index greater than 3.5 and an extinction coefficient less than 0.005 under a wavelength of 700 nm to 1800 nm.

The purpose of the present invention is to provide a perpendicular magnetic recording medium which uses an Ru seed layer having a (002)-oriented hcp structure, and has a magnetic recording layer including a (001)-oriented L1.sub.0 ordered alloy suitable to perpendicular magnetic recording. The magnetic recording medium of the present invention includes a substrate, a first seed layer containing Ru, a second seed layer containing ZnO, a third seed layer containing MgO, and a magnetic recording layer containing an ordered alloy, in this order, the first seed layer having the (002)-oriented hexagonal closest packed structure.

A material includes a transparent substrate coated with a stack of thin layers including at least one functional coating including at least one silver-based metal functional layer, and at least one niobium-based metal or nitride functional layer.

The purpose of the present invention is to provide a perpendicular magnetic recording medium which uses an Ru seed layer having a (002)-oriented hcp structure, and has a magnetic recording layer including a (001)-oriented L1.sub.0 ordered alloy suitable to perpendicular magnetic recording. The magnetic recording medium of the present invention includes a substrate, a first seed layer containing Ru, a second seed layer containing ZnO, a third seed layer containing MgO, and a magnetic recording layer containing an ordered alloy, in this order, the first seed layer having the (002)-oriented hexagonal closest packed structure.

A subject matter of the invention is a glass-ceramic sheet provided, on at least a portion of at least one of its faces, with a coating of thin layers comprising at least one thin functional layer composed of a metal based on niobium metal Nb, or of an oxide based on a niobium oxide NbO.sub.x in which x is at most 0.5, the or each thin functional layer being framed by at least two thin layers made of dielectric materials, the physical thickness of the thin functional layer or, if appropriate, the combined physical thickness of all the thin functional layers being within a range extending from 8 to 15 nm.

A layered product includes a substrate including a first surface and second surface that face each other, wherein the layered product includes a metal film on the first surface of the substrate, wherein gaps are dispersed between the substrate and the metal film, the gaps optically affecting light in a visible light region, wherein, when the layered product is measured from the second surface of the substrate, an absorption ratio with respect to visible light, the absorption ratio being an average value in a range of wavelength from 400 nm to 700 nm, is greater than or equal to 50%, reflectance, the reflectance being an average value in a range of wavelength from 400 nm to 700 nm, is less than or equal to 40%, and brightness L* of a D65 light source in a visual field of 10 degrees is less than or equal to 70.