Abstract: [Summary] [Problem] An object is to make a film thinner while keeping the function as an auxiliary recording layer and increase an SNR. [Solution] A structure of the perpendicular magnetic disk 100 according to the present invention includes, on a base 110, a granular magnetic layer 160 and an auxiliary recording layer 180 disposed above the granular magnetic layer, the granular magnetic layer having a granular structure in which a non-magnetic substance having an oxide as a main component is segregated around magnetic particles having a CoCrPt alloy as a main ingredient growing in a columnar shape to form a grain boundary part, and the auxiliary recording layer having a CoCrPtRu alloy as a main component and further containing, as a accessory component, a metal forming passivity and not being an antiferromagnet.

Abstract: A magnetic disk is provided which is excellent in durability of the magnetic disk or particularly in LUL durability and CFT characteristics and has high reliability under a decreased floating amount of the magnetic head accompanying the recent rapid increase in a recording density and extremely severe environmental resistance accompanying diversification of the applications. The magnetic disk of the present invention is a magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate, and 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.

Abstract: A lubricant compound for a magnetic disk is provided which can realize further reduction of the magnetic spacing and moreover, has high reliability under a lower floating amount of the magnetic head involved with the recent rapid increase in the recording density and under extremely severe environmental resistance involved with diversification of the applications. A lubricant compound is contained in a lubrication layer of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, and the lubricant compound contains a component A and a component B expressed by the following chemical formula: [Chemical formula] 1 Component A: X=OH Component B: X=OCH2CH(OH)CH2OH and a component C made of a specific compound having a phosphezene ring in the structure thereof.

Abstract: 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.

Abstract: The invention provides a magnetic disk that solves (1) a problem of cross-talk that cannot be solved even by an existing thermally assisted recording method or a discrete method (DTM or the like), (2) a problem of surface flatness, which an existing embedding type DTM or the like has, and (3) a problem of a difference in thermal expansion coefficient between materials when a thermally assisted method is applied to the DTM, and that (4) does not necessitate a special medium structure, and is excellent in a surface flatness and economically and functionally high in realizability. A DTM manufactured by ion implantation is excellent in the surface flatness, and can solve the cross-talk problem by conducting the thermally assisted recording at a temperature between a Curie temperature (Tcn) of a portion where ions are implanted (non-recording region) and a Curie temperature (Tcr) of a portion where ions are not implanted (recording region).

Abstract: An evaluation method that can easily evaluate properties of a carbon protective film and a lubricant on a magnetic-disk surface or particularly, an evaluation method of a magnetic disk in which the properties of the magnetic-disk surface can be evaluated accurately so that a strict demand for interactions between the magnetic-disk surface and a head can be met is provided. In a state in which an element portion of the magnetic head provided with the head element portion that projects by thermal expansion is projected, after being brought into contact with a predetermined radial position on the surface of the rotating magnetic disk, the head is further made to perform seeking in a state in which the element portion is projected by a specified amount, whereby the properties of the carbon film or the lubricant formed on the magnetic-disk surface is evaluated.

Abstract: Provided is a magnetic recording medium which maintains high S/N ratio and coercive force (Hc) and has high recording density, even with fine magnetic particles, by further improving crystal orientation of a magnetic recording layer. The magnetic recording medium is provided with an orientation control layer (16), a nonmagnetic under layer (18), and a magnetic recording layer (22) on a substrate. The orientation control layer (16) has an fcc structure and a (111) plane parallel to the substrate. The under layer (18) has an hcp structure and a (0001) plane parallel to the substrate. An atomic distance of the (111) plane of the orientation control layer (16) is ?0.2 ? to +0.15 ? to a lattice spacing of the under layer (18).

Abstract: An object of the present invention is to further improve a recording density in a magnetic disk apparatus using a shingle write system. In a magnetic disk apparatus including a magnetic disk, a recording head that writes information on the magnetic disk, and a controller that controls a writing operation of the recording head to the magnetic disk, the controller controls the writing operation such that the recording head writes information on a region including a target track and a portion of track adjacent thereto in an overlapping manner while position-shifting in a radial direction of the magnetic disk and a first writing frequency to a track on which information is last written is higher than a second writing frequency to another track.

Abstract: An object of the invention is to achieve thinning while maintaining a function required for an auxiliary recording layer, thereby achieving improvement of SNR. A configuration of a method for manufacturing a perpendicular magnetic disk 100 according to the invention includes a granular magnetic layer forming step, on a base 110, a granular magnetic layer 160 in which a grain boundary portion is formed by segregation of a non-magnetic substance containing an oxide as a main component around magnetic particles containing a CoCrPt alloy grown in a columnar shape as a main component; an auxiliary recording layer forming step of forming an auxiliary recording layer 180 that contains a CoCrPtRu alloy as a main component and has a film thickness of 1.5 to 4 nm above the granular magnetic layer; and a heating step of heating the base formed with the auxiliary recording layer in a temperature range of 210 to 250° C.

Abstract: [Problem] To make a film thinner while keeping a function as an auxiliary recording layer, and improve an SNR and an overwrite characteristic. [Solution] A typical structure of a perpendicular magnetic disk according to the present invention includes, on a base, a granular magnetic layer 160 and an auxiliary recording layer 180 disposed on the granular magnetic layer 160. The granular magnetic layer 160 has a granular structure in which a grain boundary part is formed with segregation of a non-magnetic substance having an oxide as a main component around magnetic particles having a CoCrPt alloy a main component growing in a columnar shape. The auxiliary recording layer 180 has a CoCrPtRu alloy as a main component, and has a film thickness of 1.5 nm to 4.0 nm.

Abstract: A protection layer containing carbon as a major component is deposited by plasma CVD. The protection layer has film quality such that, when a spectrum is obtained by excluding photoluminescence from a Raman spectrum in a wavenumber band from 900 cm?1 to 1800 cm?1 obtained by exciting the protection layer with an argon ion laser beam having a wavelength of 514.5 nm and the spectrum is subjected to waveform separation by the Gaussian function to split a D peak appearing around 1350 cm?1 and a G peak appearing around 1520 cm?1, the ratio Dw/Gw between a half width Dw of the D peak and a half width Gw of the G peak exceeds 0 and is not greater than 2.7.

Abstract: 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.

Abstract: A magnetic recording medium (10) has a substrate (12) and a perpendicular magnetic recording layer (30) formed over the substrate (12). The perpendicular magnetic recording layer (30) has a granular layer (20) in which a magnetic signal is recorded and a continuous film layer (24) magnetically coupled to the granular layer (20). The continuous film layer (24) has hard magnetic portions (204) formed in positions corresponding to the recording regions where magnetic signals are recorded in the granular layer (20) and magnetic shield portions (202) formed between the hard magnetic portions (204), each having a magnetization curve whose slope is larger than those of the hard magnetic portions in the region where the applied magnetic filed is zero when the magnetization curve is measured, and each having a residual magnetic polarization smaller than those in the hard magnetic portions.

Abstract: [Problem] The concentration distribution in a perpendicular direction of ions implanted in a magnetic recording layer of a perpendicular magnetic recording medium is made a suitable one corresponding to a layer implanted with ions.

Abstract: The present invention provides a perpendicular magnetic recording medium that can reduce noise by further size reduction and isolation of magnetic grains in a magnetic recording layer and can increase the recording density by improvement of the SNR. A typical configuration of a perpendicular magnetic recording medium according to the present invention is a perpendicular magnetic recording medium having a magnetic recording layer with a granular structure in which non-magnetic grain boundary portions are formed between magnetic grains that have grown continuously in a columnar shape, wherein the grain boundary portions contain a plurality of kinds of oxides.

Abstract: An object of the present invention is to achieve thinning of an auxiliary recording layer while maintaining the function thereof to improve SNR. A representative configuration of a perpendicular magnetic disk according to the present invention includes, on abase, a granular magnetic layer 160, and a auxiliary recording layer 180 disposed as an upper layer of the granular magnetic layer 160, wherein the granular magnetic layer 160 has a granular structure in which a grain boundary portion is formed by segregation of a non-magnetic substance containing an oxide as a main component around magnetic particles containing a CoCrPt alloy grown in a columnar shape as a main component, and the auxiliary recording layer 180 contains a CoCrPtRu alloy as a main component and has a film thickness of 1.5 nm to 4.0 nm.

Abstract: A vertical magnetic recording disc (100) includes a base (10), a magnetic recording layer (22), and a medium protection layer (26). The magnetic recording layer (22) is a ferromagnetic layer having a granular structure where a granular portion is formed. The medium protection layer (26) contains nitrogen (N) atoms and carbon (C) atoms with a number ratio (N/C) in a range from 0.050 to 0.150. In a Raman spectrum obtained by exciting the medium protection layer (26) by argon ion laser light of wavelength 514.5 nm, from which a fluorescence is removed, the peak ratio Dh/Gh is in a range from 0.70 to 0.95, when a D peak Dh appearing in the vicinity of 1350 cm?1 is separated from G peak Gh appearing in the vicinity of 1520 cm?1 by the Gauss function.

Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium the SNR of which is further improved while a high coercive force Hc is secured so that a higher recoding density can be achieved.

Abstract: The present invention provides a lubricant for forming a lubricating layer which is useful in preventing fly and stiction and/or corrosion at an extremely small flying height of 10 nm or less, which is prevented from migrating at a high rotational speed of 5400 rpm or more, which has high adhesion, and which is suitable for a load/unload method. A crude lubricant containing at least one perfluoropolyether is degassed and then purified. Alternatively, a liquid crude lubricant containing at least one perfluoropolyether is purified by vaporizing the crude lubricant and then liquefying the vapor of the perfluoropolyether within a distance less than the mean free path of molecules of the perfluoropolyether. A magnetic disk is prepared in such a manner that a carbonaceous protective layer is formed above a substrate and a lubricating layer is formed on the protective layer using of the lubricant. The lubricant contains the perfluoropolyether and has a molecular weight distribution of 1.3 or less.

Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium the SNR of which is improved by reducing noise thought to be due to an auxiliary recording layer so that a higher recording density can be achieved, and a method of manufacturing the same. In order to achieve the above object, a representative configuration of a perpendicular magnetic recording medium 100 according to the present invention includes, on a base, at least a magnetic recording layer 122 having a granular structure in which a non-magnetic grain boundary portion is formed between crystal particles grown in a columnar shape; a non-magnetic split layer 124 disposed on the magnetic recording layer 122 and containing Ru and oxygen; and an auxiliary recording layer 126 that is disposed on the split layer 124 and that is magnetically approximately continuous in an in-plane direction of a main surface of the base 110.