Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium improved for fly ability, high in read signal quality, and capable of suppressing magnetic decay of recorded magnetization to be caused by stray fields. In one embodiment, a perpendicular recording layer is formed over a substrate with a soft magnetic underlayer therebetween, then an amorphous or nano-crystalline layer is formed between the substrate and the soft magnetic underlayer. The soft magnetic underlayer includes first and second amorphous soft magnetic layers, as well as a nonmagnetic layer formed between those first and second amorphous soft magnetic layers. The first and second amorphous soft magnetic layers are given uniaxial anisotropy in the radial direction of the substrate respectively and coupled with each other antiferromagnetically.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium improved for fly ability, high in read signal quality, and capable of suppressing magnetic decay of recorded magnetization to be caused by stray fields. In one embodiment, a perpendicular recording layer is formed over a substrate with a soft magnetic underlayer therebetween, then an amorphous or nano-crystalline layer is formed between the substrate and the soft magnetic underlayer. The soft magnetic underlayer includes first and second amorphous soft magnetic layers, as well as a nonmagnetic layer formed between those first and second amorphous soft magnetic layers. The first and second amorphous soft magnetic layers are given uniaxial anisotropy in the radial direction of the substrate respectively and coupled with each other antiferromagnetically.

Abstract: According to one embodiment, a PMRM includes a substrate, a soft magnetic underlayer above the substrate, an underlayer above the soft magnetic underlayer, an oxide-containing magnetic layer above the underlayer, and a ferromagnetic layer above the magnetic layer having no oxides. The underlayer controls orientation and segregation of the magnetic layer. The oxide-containing magnetic layer comprises at least two or more magnetic layers, a Cr concentration of the magnetic layer adjacent to the ferromagnetic metal layer is between about 23 at. % and about 32 at. %, and a difference between the Cr concentration of the magnetic layer adjacent to the ferromagnetic metal layer and a magnetic layer having a lowest Cr concentration among the at least three magnetic layers is less than about 25 at. %, the magnetic layer with a lowest Cr concentration has a granular structure, and a nucleation field is greater than about 159.2 kA/m.

Abstract: A perpendicular magnetic recording medium is manufactured having excellent thermal stability and recording performances across the entire disk surface. In one embodiment, the recording layer includes at least two layers deposited by using a reactive sputtering method under an oxygen-containing atmosphere at a deposition rate larger than the second recording layer which is formed on the first recording layer while depositing the first recording layer on the intermediate layer.

Abstract: Embodiments of the present invention provide a perpendicular magnetic recording medium that reduces the noise of granular recording layers, obtains sufficient overwrite characteristic that suppresses an increase in the magnetic cluster size, and allows high-density recording. According to one embodiment, a perpendicular magnetic recording medium comprising substrate having thereon at least soft magnetic layer, nonmagnetic intermediate layer, a perpendicular recording layer and protective layer formed in that order. The perpendicular recording layer consists of three or more layers of first recording layer, a second recording layer, and a third recording layer from the side nearer to the substrate. The first recording layer and the second recording layer have a granular structure comprising a grain boundary of an oxide surrounding ferromagnetic crystal grains containing Co and Pt, and the third recording layer has a non-granular structure mainly comprising Co and not containing an oxide.

Abstract: Soft magnetic film fabricated with preferred uniaxial anisotropy for perpendicular recording. One type of cathode design has a field direction that is parallel to the direction of the Hex of the second SUL with a magnetically-pinned first SUL. In addition, SUL structures having low AP exchange energy also are disclosed. The SUL structure combines the cathode field direction of the SUL2 with the pinned SUL1. The SUL1 is magnetically pinned to the pinning layer and the pinning direction is parallel to the direction of the cathode field applied during deposition of the SUL1. High Hc ferro-magnetic materials may be deposited onto a heated substrate that is magnetized along the radial direction by the cathode field. The pinning field may be higher than the cathode field, indicating that the cathode field during deposition of the SUL2 cannot disturb the magnetic state of the SUL1 pinned to pinning layer.

Abstract: Embodiments of the present invention help to provide a perpendicular magnetic recording medium in which a perpendicular magnetic recording layer is formed via a soft magnetic under-layer on a disk substrate, whereby the error rate is reduced and high density recording is enabled. According to one embodiment, the disk substrate is textured so that the center line average height (Ra) is from 0.05 nm to 0.2 nm, in which the soft magnetic under-layer is amorphous and has a film thickness from 2.5 nm to 10 nm, and the magnetic field for saturation (Hs) of the perpendicular magnetic recording layer is 7 kOe or less.

Abstract: Embodiments of the present invention provide a perpendicular magnetic recording medium having an improved writing property due to the exchange spring effect and capable of stable production. According to one embodiment, a perpendicular magnetic recording medium includes a non-magnetic substrate; an adhesion layer; a soft magnetic underlayer; a seed layer; and intermediate layer; a magnetic recording layer at least including a perpendicular recording layer, a writing assist layer, and a magnetic coupling layer disposed between the perpendicular recording layer and the writing assist layer; a protective layer, and a lubrication layer, in which the saturation magnetization of the magnetic coupling layer is lower than the saturation magnetization of the writing assist layer, the saturation magnetization of the magnetic coupling layer is 300 kA/m (300 emu/cc) or lower, and the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or lower.

Abstract: Fluctuation of read/write characteristics during mass production is suppressed for a perpendicular magnetic recording medium having a perpendicular recording layer of a bi-layered structure, in which a first Co—Cr—Pt alloy magnetic layer containing an oxide and a second Co—Cr—Pt magnetic layer are formed successively. According to one embodiment, in a perpendicular magnetic recording medium, an adhesion layer, a soft magnetic underlayer, a seed layer, an intermediate layer, a perpendicular recording layer, a protective layer, and a lubricating layer are successively formed on a substrate. The perpendicular recording layer has a bi-layered structure in which a first Co—Cr—Pt alloy magnetic layer containing an oxide and a second Co—Cr—Pt alloy magnetic layer containing a marker element for measurement of a thickness selected from Mo, Mn, and V are successively formed, and the content of the marker element for measurement of thickness is about 1.5 at % or more and about 5 at % or less.

Abstract: There is provided a perpendicular magnetic recording medium comprising a non-magnetic layer having a face-centered cubic structure, an antiferromagnetic layer provided on the non-magnetic layer, a soft magnetic underlayer provided on the antiferromagnetic layer, and a perpendicular recording layer provided on the soft magnetic underlayer, which magnetic recording medium makes it possible to realize a recording density not less than 50 Gb/in2 and makes the error rate thereof low while suppressing the spike noise.

Abstract: A magnetic recording/reproducing apparatus is disclosed with high storage capability. The apparatus also prevents fluctuation of readback output and decay of magnetization or erasure of recorded magnetization in the recording layer. A soft magnetic underlayer and a perpendicular recording layer are formed in specific order on the substrate of a magnetic disk. The soft magnetic underlayer has a triple-layered structure in which a domain control layer, including an anti-ferromagnetic layer, is sandwiched between two first and second soft magnetic layers. The thickness of the first and second soft magnetic layers (d1, d2) is between 25 nm and 150 nm and a ratio of d1/d2 is within a range of 0.3 to 1.5. Accordingly, magnetic domains in the soft magnetic underlayer of a perpendicular magnetic recording medium can be controlled and magnetic domain wall motion can be inhibited.

Abstract: A magnetic recording medium having a high coercive force and being capable of high-density writing/reading has a substrate, a soft magnetic layer, a non-magnetic intermediate layer, a magnetic layer, a protective layer, and a lubricating layer. The magnetic layer is characterized by stacking fault density and dispersion of particle diameters. The stacking fault density should preferably be no larger than 0.05, and the dispersion of particle diameters should preferably be no larger than 0.4. The magnetic recording medium has a coercive force larger than 4000 Oe, is highly stable to thermal decay, and has a recording density in excess of 50 Gbit/in2.

Abstract: Provided are a double-layer perpendicular magnetic recording medium having a high medium S/N at an areal recording density of 50 Gbits or more per square inch, and a magnetic storage apparatus having excellent reliability with a low error rate. The perpendicular magnetic recording medium is formed by sequentially laminating a domain control layer, an amorphous soft magnetic underlayer, an intermediate layer, and a perpendicular recording layer on a substrate. The domain control layer is a triple-layer film formed by laminating a first polycrystalline soft magnetic layer, a disordered antiferromagnetic layer, and a second polycrystalline soft magnetic layer from a substrate side.

Abstract: A soft magnetic underlayer includes a first amorphous soft magnetic layer to which an exchange bias magnetic field is applied directly from an antiferromagnetic layer or via a ferromagnetic layer, and a second amorphous soft magnetic layer which is formed on the first amorphous soft magnetic layer via a non-magnetic layer. The first amorphous soft magnetic layer and the second amorphous soft magnetic layer are antiferromagnetically coupled.

Abstract: A double layer perpendicular magnetic recording medium having a high medium S/N ratio at a recording density of 50 Gb/in2 or higher and a magnetic storage apparatus with a lower error rate and excellent reliability are provided. In a perpendicular magnetic recording medium in which a soft magnetic underlayer 12, an intermediate layer 13, and a perpendicular magnetic recording layer 14 are sequentially formed on a substrate 11, the intermediate layer 13 is made to be a non-magnetic amorphous alloy, in which Ni is a main component and Zr is contained, and the soft magnetic underlayer 12 is constituted of ferromagnetic nan-crystals precipitated by annealing.

Abstract: A magnetic recording system includes an in-plane magnetic recording medium having a magnetic layer fabricated on a single underlayer or on a plurality of underlayers respectively fabricated on a substrate; a driver unit for driving the in-plane magnetic recording medium in a write direction; a magnetic head having a read unit and a write unit; a unit for moving the magnetic head relative to the in-plane magnetic recording medium; and a read/write signal processing unit for reading an output signal from the magnetic head and writing an input signal to the magnetic recording media, wherein the read unit of the magnetic head is a magnetoresistive head and the single underlayer or at least one of the plurality of underlayers is made of Co-containing amorphous material or fine crystal material, or is made of alloy material, the alloy material having as the main components at least one element selected from a group consisting of Cr, Mo, V and Ta and containing at least one element selected from a group consisting o

Abstract: In a magnetic storage apparatus having a magnetic recording medium, a drive unit for driving this medium in a prespecified recording direction, a magnetic head assembly including a recorder section and reproduction section, means for causing the magnetic head to move relatively with respect to the magnetic record medium, and a record/playback signal processor means for performing signal inputting to the magnetic head and for effecting reproduction of an output signal from the magnetic head, the reproduction section of said magnetic head is composed of a magnetic head of the magnetoresistance effect type, while said magnetic record medium is structured including a substrate and a magnetic layer formed thereover with one or several underlayers being sandwiched therebetween, wherein at least one of the underlayers is a specific layer that is made of amorphous or microcrystalline materials containing therein Ni as the principal or main component thereof and further containing at least one kind of element as selec

Abstract: A perpendicular recording medium includes a perpendicular recording layer formed over a substrate through a soft magnetic underlayer, the soft magnetic underlayer then being arranged to include a plurality of soft magnetic layers physically separated by a non-magnetic layer, and further, the soft magnetic layers being formed of nanocrystals, with these arrangements, local magnetic loops are formed between the soft magnetic layers that are adjacent to each other through the non-magnetic layer, thereby suppressing spike noise and modulation that arises from the soft magnetic underlayer.

Abstract: A perpendicular magnetic recording medium is manufactured having excellent thermal stability and recording performances across the entire disk surface. In one embodiment, the recording layer includes at least two layers deposited by using a reactive sputtering method under an oxygen-containing atmosphere at a deposition rate larger than the second recording layer which is formed on the first recording layer while depositing the first recording layer on the intermediate layer.

Abstract: Embodiments of the invention provide a manufacturing method which permits a high quality perpendicular magnetic recording medium to be manufactured with a high yield by preventing abnormal discharge which sputters particles from the target. In one embodiment, while the perpendicular magnetic recording medium is formed, DC pulses are applied to the target. During the reversal period (Reversal Time) between sputtering periods, a voltage of the opposite polarity is applied. During the sputtering period, a negative voltage is applied which biases the target surface to a negative potential, causing Ar+ to collide with and sputter CoCrPt and SiO2 for deposition on the intermediate layer. The top surface of the insulation material (SiO2) on the target is charged by Ar+ to have a voltage larger than the target voltage. However, arcing can be prevented since the charge on the surface of the insulation material is neutralized due to a positive voltage applied to the target during the non-sputtering period.