Abstract: An HDD includes a magnetic head, and a magnetic recording medium. The recording medium includes a recording magnetic layer, and a recording assist magnetic layer, the recording assist magnetic layer generates a high-frequency magnetic field by means of a recording field from the magnetic head, and a recording assist action acts on the recording magnetic layer.

Abstract: A medium having high medium S/N and excellent corrosion resistance is achieved. In one embodiment, an adhesion layer, a soft magnetic layer, an intermediate layer, a magnetic recording layer, and a protective layer are deposited, in order, on a substrate. The soft magnetic underlayer consists at least of two soft magnetic layers, the first soft magnetic layer formed on the recording layer side being composed of an amorphous alloy containing 85 at. % or less of Co, and the second soft magnetic layer formed on the substrate side being composed of an alloy containing more than 85 at. % of Co.

Abstract: Embodiments of the invention ensure that a perpendicular magnetic recording medium having a granular magnetic recording layer made of CoCrPt alloy and Si oxide provides both high SNR and thermal stability. In one embodiment, a substantially amorphous grain boundary layer of a magnetic recording layer made of CoCrPt alloy and Si oxide contains a ferromagnetic element in a concentration from about 30 at. % to 50 at. % or more preferably from about 35 at. % to 47 at. %, so that intergrain exchange interaction takes place moderately. As a consequence, SNR of 18 dB or more and thermal stability of 3%/decade or less are achieved.

Abstract: Embodiments of the embodiment are directed to reducing the inter-granular exchange coupling of an oxide granular medium and obtaining a high media S/N value, resulting in an areal recording density greater than 23 gigabits per square centimeter or more being achieved. In one embodiment, a magnetic recording medium comprises a structure laminating a soft-magnetic underlayer, a lower intermediate layer including Ru, an upper intermediate layer consisting of Ru crystal grains and oxide crystal grain boundaries, a magnetic recording layer consisting of crystal grains and oxide crystal grain boundaries, in order, on a substrate, growing crystal grains of the magnetic recording layer epitaxially on the Ru crystal grains of the upper intermediate layer, and growing the crystal grain boundaries of the magnetic recording layer on the crystal grain boundaries of the upper intermediate layer.

Abstract: Embodiments of the invention provide a medium which provides high media S/N and good corrosion resistance. According to one embodiment, in a perpendicular magnetic recording medium at least comprising a soft-magnetic underlayer, a seed layer, an intermediate layer, a magnetic recording layer and an overcoat layer which are stacked over a substrate in order, the magnetic recording layer has a granular structure which consists of many columnar grains of CoCrPt alloy and a grain boundary layer containing an oxide, the seed layer is made of TaNi alloy or TaTi alloy and the intermediate layer is made of Ru or Ru alloy which contains about 80 at. % Ru or more.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium that not only attains the magnetic isolation of crystal grains in a magnetic recording layer from one another in a region of the medium in which the thickness of an intermediate layer is equal to or smaller than about 20 nm but also exhibits excellent crystallographic texture and that exhibits small medium noise, excellent thermal stability, and high write-ability. In one embodiment, a perpendicular magnetic recording medium has at least a soft-magnetic underlayer, a first intermediate layer, a second intermediate layer, a third intermediate layer, and a magnetic recording layer successively formed on a substrate.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium capable of reconciling a high recording density with high thermal stability, and having a high write-ability while maintaining high magnetic anisotropy energy. In one embodiment, a perpendicular magnetic recording medium has a soft-magnetic underlayer, and magnetic recording layers, and the magnetic recording layers comprises a first recording layer containing magnetic grains oriented in a direction normal to a medium plane, and a second recording layer containing magnetic grains tilted in a cross-track direction. There can be provided a perpendicular magnetic recording medium resistant to thermal fluctuation, small in medium noise, and excellent in write-ability.

Abstract: Embodiments of the invention are directed to a medium which provides high media S/N and good corrosion resistance. According to one embodiment, in a perpendicular magnetic recording medium at least comprising a soft-magnetic underlayer, a seed layer, an intermediate layer, a magnetic recording layer and an overcoat layer which are stacked over a substrate in order, the magnetic recording layer has a granular structure which includes many columnar grains of CoCrPt alloy and a grain boundary layer containing an oxide, the seed layer is made of TaNi alloy or TaTi alloy and the intermediate layer is made of Ru or Ru alloy which contains 80 at. % Ru or more.

Abstract: Embodiments in accordance with the present invention provide a perpendicular magnetic recording medium which is easy to record, offers superior thermal stability of recording magnetization, and allows high-density recording. In one embodiment, a perpendicular magnetic layer with controlled magnetic properties is used as a magnetic storage layer of a perpendicular magnetic recording medium, the magnetic properties having been controlled such that an indicator ?hsw [%] of the dispersion of magnetization switching fields in the perpendicular magnetic layer and an indicator Dn [nm] of the intensity of exchange interactions, in film surface directions, in the perpendicular magnetic layer satisfy inequalities ?hsw/27+Dn/90<1, and Dn>20. The indicators can be measured using a magnetometer.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium that not only attains the magnetic isolation of crystal grains in a magnetic recording layer from one another in a region of the medium in which the thickness of an intermediate layer is equal to or smaller than about 20 nm but also exhibits excellent crystallographic texture and that exhibits small medium noise, excellent thermal stability, and high write-ability. In one embodiment, a perpendicular magnetic recording medium has at least a soft-magnetic underlayer, a first intermediate layer, a second intermediate layer, a third intermediate layer, and a magnetic recording layer successively formed on a substrate.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium that not only attains the magnetic isolation of crystal grains in a magnetic recording layer from one another in a region of the medium in which the thickness of an intermediate layer is equal to or smaller than about 20 nm but also exhibits excellent crystallographic texture and that exhibits small medium noise, excellent thermal stability, and high write-ability. In one embodiment, a perpendicular magnetic recording medium has at least a soft-magnetic underlayer, a first intermediate layer, a second intermediate layer, a third intermediate layer, and a magnetic recording layer successively formed on a substrate.

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: Embodiments in accordance with the present invention provide a perpendicular magnetic recording medium which is easy to record, offers superior thermal stability of recording magnetization, and allows high-density recording. In one embodiment, a perpendicular magnetic layer with controlled magnetic properties is used as a magnetic storage layer of a perpendicular magnetic recording medium, the magnetic properties having been controlled such that an indicator ?hsw [%] of the dispersion of magnetization switching fields in the perpendicular magnetic layer and an indicator Dn [nm] of the intensity of exchange interactions, in film surface directions, in the perpendicular magnetic layer satisfy inequalities ?hsw/27+Dn/90<1, and Dn>20. The indicators can be measured using a magnetometer.

Abstract: A medium having high medium S/N and excellent corrosion resistance is achieved. In one embodiment, an adhesion layer, a soft magnetic layer, an intermediate layer, a magnetic recording layer, and a protective layer are deposited, in order, on a substrate. The soft magnetic underlayer consists at least of two soft magnetic layers, the first soft magnetic layer formed on the recording layer side being composed of an amorphous alloy containing 85 at. % or less of Co, and the second soft magnetic layer formed on the substrate side being composed of an alloy containing more than 85 at. % of Co.

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: A double-layer perpendicular magnetic recording medium suitable for high density recording is obtained. In one embodiment, a granular recording medium is formed on a undercoating layer, in which a first metal composed of Pt, Pd, or an alloy thereof and a second metal composed of Cr or V are included and their composition is 15%<B/(A+B)<30% when the atomic fraction of the first metal is assumed to be A and the atomic fraction of the second metal is assumed to be B.

Abstract: A magnetic recording medium having a substrate, an under-layer formed on the substrate, a magnetic layer formed on the substrate and a protective layer formed on the magnetic layer. The magnetic layer comprises Co, Cr and Pt with a thickness being from 10 nm to 22 nm. Further, a coercivity of the magnetic layer is not less than 2000 Oe, and a fluctuation field of magnetic viscosity at a field strength equal to remanence coercivity or coercivity is not less than 30 Oe.

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: Embodiments of the invention provide a medium which provides high media S/N and good corrosion resistance. According to one embodiment, in a perpendicular magnetic recording medium at least comprising a soft-magnetic underlayer, a seed layer, an intermediate layer, a magnetic recording layer and an overcoat layer which are stacked over a substrate in order, the magnetic recording layer has a granular structure which consists of many columnar grains of CoCrPt alloy and a grain boundary layer containing an oxide, the seed layer is made of TaNi alloy or TaTi alloy and the intermediate layer is made of Ru or Ru alloy which contains about 80 at. % Ru or more.

Abstract: The present invention restricts defect density on the magnetic disk based on predetermined polishing conditions by applying a magnetic field to the entire surface of a magnetic disk in a direction vertical thereto, rotating the magnetic disk, loading a magnetic head to the magnetic disk, reproducing signals from the magnetic disk, processing the reproduced signals by a waveform analyzer, counting pulse waveforms of 0.9 times or more a servo-bit length at ½ threshold value of an average output, and measuring the defect density on the magnetic disk giving an undesired effect on the I/O performance of the magnetic disk drive. In a case of a magnetic recording medium using a vertical magnetic recording system, even with fine defect of magnetic layer, a servo pattern cannot be judged correctly. This provides degradation of the I/O performance of increasing the time necessary for reading out large capacity data, lowering the performance of the entire magnetic disk drive.