Various embodiments provide for a heat assisted magnetic recording (HAMR) media comprising: a magnetic recording layer; a barrier layer disposed under the magnetic recording layer; a first underlayer disposed under the barrier layer; and an amorphous seedlayer disposed under the first underlayer. For some embodiments, the recording medium may comprise: a magnetic recording layer including FePt alloy, a CoPt alloy, or a FePd alloy; a barrier layer including MgO, TiC, TiN, CrN, TiCN, β-WC, TaC, HfC, ZrC, VC, NbC, or NiO; a first underlayer including RuAl-oxide, NiAl, FeAl, AlMn, CuBe, or AlRe; or an amorphous seedlayer including a Cr—X alloy, where X comprises Al, B, C, Cu, Hf, Ho, Mn, Mo, Ni, Ta, Ti, V, W, or Ru.

Underlayers for heat assisted magnetic recording (HAMR) media

A perpendicular magnetic recording medium comprises a magnetic recording layer that records a signal, an underlayer formed of Ru or Ru compound below the magnetic recording layer, a non-magnetic layer formed of a non-magnetic material below the underlayer to control crystal orientation of the underlayer, a soft magnetic layer provided below the non-magnetic layer, and a substrate on which the magnetic recording layer, the underlayer, the non-magnetic layer, and the soft magnetic layer are formed. The non-magnetic layer comprises a first non-magnetic layer formed above the soft magnetic layer and a second non-magnetic layer formed above the first non-magnetic layer. The first non-magnetic layer is formed of amorphous Ni compound while the second non-magnetic layer is formed of crystalline Ni or crystalline Ni compound.

Perpendicular magnetic recording medium and method of manufacturing the same

In a perpendicular magnetic recording medium which includes a substrate ( 1 ) of a nonmagnetic material, first and second nonmagnetic underlayers ( 4 and 5 ) formed on the substrate, and a perpendicular magnetic recording layer ( 6 ) formed on the first and the second nonmagnetic underlayers, the first nonmagnetic underlayer is made of an amorphous nonmagnetic metal material containing a metal element which forms a face-centered cubic (fcc) crystal structure by a simple substance. The second nonmagnetic underlayer is formed on the first nonmagnetic underlayer in contact with the first nonmagnetic underlayer and made of a nonmagnetic material containing a hexagonal close packed structure. The perpendicular magnetic recording layer is formed on the second nonmagnetic underlayer in contact with the second nonmagnetic layer.

Perpendicular magnetic recording medium

An object of the present invention is to provide a perpendicular magnetic recording medium in which each space between crystal grains of a first magnetic recording layer is so designed as to allow the layer to also have a function as a continuous layer, and a method of manufacturing a perpendicular magnetic recording medium. In a perpendicular magnetic recording medium 100 according to the present invention, a first magnetic recording layer 122 a and a second magnetic recording layer 122 b are ferromagnetic layers each having a granular structure in which a grain boundary part made of a non-magnetic substance is formed between crystal grains each grown in a column shape and, in the first magnetic recording layer 122 a , an intergranular distance defined by an average of shortest distances between grain boundary parts each between a crystal grain and its adjacent crystal grain is equal to or shorter than 1 nm.

Perpendicular magnetic recording medium and process for manufacture thereof

Provided are a magnetic disk comprising a granular magnetic recording layer which causes less noise even with a recording capacity thereof of 250 G or more bits per square inch; and a method for manufacturing the same. The magnetic disk according to the present invention comprises: a granular magnetic recording layer ( 20 ) which is formed on a disk substrate 10 directly or via an intermediate layer and which has non-magnetic regions between granular columnar particles; and an auxiliary recording layer ( 22 ) which is formed on the granular magnetic recording layer 20 and which causes exchange interaction among the granular columnar particles, wherein the auxiliary recording layer ( 22 ) contains 0.1 to 3 moles of oxygen.

Magnetic disk and method for manufacturing same

A lubricant for magnetic disks which can form a lubricating layer having a reduced thickness while attaining a high coverage and is excellent in heat resistance and adhesion to a protective layer. The lubricant for magnetic disks comprises a perfluoropolyether compound in which the relationship between the number-average molecular weight and the standardized value of the number of hydroxy groups contained in the molecule satisfies the following: the number-average molecular weight is in the range of 1,000-6,000; the standardized value of the number of hydroxy groups contained in the molecule is 180 or higher; and the compound is in a region located below the line connecting the point where the number-average molecular weight is 1,000 and the standardized value of the number of hydroxy groups in the molecule is 400 to the point where the number-average molecular weight is 6,000 and the standardized value of the number of hydroxy groups in the molecule is 1,600. The compound has at least one hydroxy group around the center of the molecular chain.

Lubricant for magnetic disk, process for producing the same, and magnetic disk

Provided is a magnetic disk that is excellent in durability, particularly in LUL durability and CFT properties, and thus has high reliability despite the low flying height of a magnetic head following the rapid increase in recording density in recent years and despite the very strict environmental resistance following the diversification of applications. A magnetic disk (10) has at least a magnetic layer (6), a carbon-based protective layer (7), and a lubricating layer (8) provided in this order over a substrate (1). The lubricating layer (8) contains a compound having a perfluoropolyether main chain in a structure thereof and having a polar group other than at ends of a molecule thereof.

Magnetic disk and method of manufacturing the same

A magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. The lubrication layer is a film formed by a lubricant that contains two types of compounds having a perfluoropolyether main chain in the structure, a molecular weight distribution of the two types in total being within a range of 1 to 1.2. The two types of compounds include a compound a having a hydroxyl group at the end and a compound b having a number average molecular weight smaller than the number average molecular weight of the compound a and not more than 1500. A content of the compound b in the two types of compounds is not more than 10%.

Magnetic disk and manufacturing method thereof

A lubricant for a magnetic disk that is excellent in heat resistance and is suitably used in a magnetic disk to be mounted on a magnetic recording device of a thermally assisted magnetic recording system and a magnetic disk provided with a lubricant layer containing this lubricant. The lubricant for a magnetic disk contains a compound where perfluoropolyether groups each having a perfluoropolyether main chain in its structure and a phosphazene ring at an end are linked to each other through a linking group. The linking group is an aliphatic group or a phosphazene ring. In a magnetic disk having at least a magnetic recording layer, a protective layer, and a lubricant layer on a substrate, the lubricant layer contains the lubricant for a magnetic disk.

Lubricant for magnetic disk and magnetic disk

A lubricant compound for magnetic disks which render a further reduction in magnetic spacing possible and which have high reliability under conditions in which the flying height of magnetic heads is small due to recent rapid increase in recording density and under the situation where extremely severe environmental resistance is required due to diversification of uses The lubricant compound is for use in a magnetic disk comprising a substrate and, disposed thereon in the following order, at least a magnetic layer, a protective layer, and a lubricating layer and is to be incorporated into the lubricating layer The lubricant compound comprises ingredient A and ingredient B both represented by chemical formula and ingredient C comprising a specific compound having a phosphazene ring in the structure

Katsushi Hamakubo

Papers

Lubricant for magnetic disk, process for producing the same, and magnetic disk

Magnetic disk and method of manufacturing the same

Magnetic disk and manufacturing method thereof

Lubricant for magnetic disk and magnetic disk

Lubricant compound for magnetic disk and magnetic disk