Wd Media (singapore) Pte. Ltd.

Tokichiro Sato

Takenori Kajiwara

Teiichiro Umezawa

Masafumi Ishiyama

Kenji Ayama

Takahiro Onoue

Junichi Horikawa

Chiyo Saito

A perpendicular magnetic disk is provided. The disk includes, on a base and in the order from bottom, a first granular magnetic layer group including a plurality of magnetic layers each having a granular structure, a non-magnetic layer having Ru or a Ru alloy as a main component, a second granular magnetic layer group including a plurality of magnetic layers each having the granular structure, and an auxiliary recording layer having a CoCrPtRu alloy as a main component. Layers closer to a front surface among the plurality of magnetic layers included in the first granular magnetic layer group having an equal or smaller content of Pt. Layers closer to the front surface among the plurality of magnetic layers included in the second granular magnetic layer group having an equal or smaller content of Pt and having an equal or larger content of an oxide.

Perpendicular magnetic recording disc

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

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 () which is formed on a disk substratedirectly or via an intermediate layer and which has non-magnetic regions between granular columnar particles; and an auxiliary recording layer () which is formed on the granular magnetic recording layerand which causes exchange interaction among the granular columnar particles, wherein the auxiliary recording layer () contains 0.1 to 3 moles of oxygen.

Magnetic disk and method for manufacturing same

A perpendicular magnetic disk that includes, on a base, a soft magnetic layer, an amorphous alloy layer, a preliminary ground layer provided on the amorphous alloy layer, a ground layer formed of Ru or a Ru-type alloy having an hcp crystal structure provided on the preliminary ground layer. A granular magnetic layer is provided on the ground layer. The amorphous alloy layer contains Ta, and the preliminary ground layer includes a first preliminary ground layer formed of Ti or a Ti alloy of microcrystals and a second preliminary ground layer formed of a Ni-type alloy of an fcc crystal structure.

Perpendicular magnetic disc

[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 diskaccording to the present invention includes, on a base, a granular magnetic layerand an auxiliary recording layerdisposed 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.

A perpendicular magnetic recording medium of the invention is characterized by having, on a disk substrate, a soft magnetic layer, a magnetic recording layer, a continuous layermagnetically continuous in the in-plane direction of the substrate, a blocking layerfor blocking shock imposed on the continuous layer, and a medium protective layercontaining carbon formed on the blocking layer.

Perpendicular magnetic recording medium and manufacturing method of the same

An object of the present invention is to provide a method of manufacturing a perpendicular magnetic recording medium () in which both of a coercive force Hc and reliability can be achieved at a higher level even with heating at the time of forming a medium protective layer () and to provide the perpendicular magnetic recording medium (). Thus, in a typical structure of the present invention, in the method of manufacturing the perpendicular magnetic recording medium () including at least a magnetic recording layer (), which is a ferromagnetic layer of a granular structure in which a non-magnetic grain boundary part is formed between crystal grains each grown in a columnar shape, and a medium protective layer () with carbon hydride as a main component in this order on a disk base (), the method includes a magnetic recording layer forming step of forming the magnetic recording layer () so that the grain boundary part contains oxides of a plurality of types and a medium protective layer forming step of forming the medium protective layer () in a state where the disk base () having the magnetic recording layer () formed thereon is heated at 160 to 200 degrees Celsius.

Method of manufacturing perpendicular magnetic recording medium and perpendicular magnetic recording medium

A method for manufacturing a perpendicular magnetic diskthat includes a step of forming, on a base, a granular magnetic layerin 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. The method also includes a step of forming an auxiliary recording layerthat 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 step of heating the base formed with the auxiliary recording layer in a temperature range of 210 to 250&#xb0; C.

Method of producing a perpendicular magnetic disc

A perpendicular magnetic recording mediumhas, over a substrate, at least a magnetic recording layerwith a granular structure in which nonmagnetic grain boundaries are formed between magnetic grains continuously grown into a columnar shape. The magnetic grains of the magnetic recording layercontain Co, Cr, and Pt. The magnetic recording layercontains at least one oxide selected from a group A including SiO, TiO, and CrO, at least one oxide selected from a group B consisting of oxides each having a larger Gibbs free energy &#x394;G than the group A, and a reducing agent adapted to reduce the oxides of the group B.

A vertical magnetic recording disc () includes a base (), a magnetic recording layer (), and a medium protection layer (). The magnetic recording layer () is a ferromagnetic layer having a granular structure where a granular portion is formed. The medium protection layer () 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 () 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 cmis separated from G peak Gh appearing in the vicinity of 1520 cmby the Gauss function.

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 (), a nonmagnetic under layer (), and a magnetic recording layer () on a substrate. The orientation control layer () has an fcc structure and a (111) plane parallel to the substrate. The under layer () has an hcp structure and a (0001) plane parallel to the substrate. An atomic distance of the (111) plane of the orientation control layer () is &#x2212;0.2 &#x212b; to +0.15 &#x212b; to a lattice spacing of the under layer ().

Magnetic recording medium

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.

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Singapore, Singapore

Tokichiro Sato