Abstract: A magnetic recording medium and a manufacturing method thereof can be formed or carried out without substrate heating. The magnetic recording medium has a seed layer of a nonmagnetic material having a bcc structure that has (211) orientation formed on a nonmagnetic substrate, an underlayer of a nonmagnetic material having a bcc structure that is different to that of the seed layer 102 and having (211) preferential orientation formed on the seed layer, an intermediate layer of a nonmagnetic material having an hcp structure that has (100) preferential orientation formed on the underlayer, and a magnetic layer of an hcp CoCr alloy that has (100) preferential orientation formed on the intermediate layer.

Abstract: A magnetic recording medium exhibiting low noise and having a sufficiently high coercive force includes a magnetic layer having a granular structure including ferromagnetic crystal grains with a hexagonal closest packed structure and a nonmagnetic grain boundary region of mainly an oxide intervening between the crystal grains. An underlayer has a body-centered cubic lattice structure. A nonmagnetic intermediate layer with the hexagonal closest packed structure includes Ru, Os, and/or Re, which are provided between the magnetic layer and the underlayer. A degree of mismatching &Dgr;=|d1−d2|/d1 is at most 10%, for instance, in a range from 2.5% to 7.0%, where d1 is a spacing of lattice planes of the crystal grains in the magnetic layer and d2 is a spacing of the lattice planes of the crystal grains in the intermediate layer.

Abstract: A magnetic recording medium is provided that exhibits excellent magnetic and electromagnetic conversion characteristics and allows stable high density recording with little effect of thermal disturbances. Specifically, a magnetic recording medium uses a substrate of plastic resin, such as polycarbonate or polyolefin, not subjected to intentional heating. A magnetic layer has a granular structure consisting of ferromagnetic crystalline grains with hexagonal closest packed structure and nonmagnetic grain boundary region of mainly oxide intervening between the ferromagnetic crystalline grains. An underlayer has a body centered cubic structure. A nonmagnetic intermediate layer with a hexagonal closest packed structure is provided between the magnetic layer 4 and the underlayer. The intermediate layer is composed of a nonmagnetic metallic substance of substantially one or more elements selected from Ru, Os, and Re.

Abstract: A magnetic recording medium and method of manufacturing thereof facilitates to prevent a film inflation from occurring in an environmental condition range between −40° C. and 80° C. and an 80% relative humidity. The magnetic recording medium includes a plastic substrate and an undercoating layer on the plastic substrate. The undercoating layer is provided with a columnar structure, which prevents water (moisture) between the plastic substrate and the undercoating layer from aggregating and, therefore, the film inflation from occurring.

Abstract: The quantity of oxide contained in a magnetic layer is controlled to control the crystal grains and the segregation structure for ensuring low noise characteristic in a granular magnetic layer of a perpendicular magnetic recording medium. The granular magnetic layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary region mainly of an oxide surrounding the ferromagnetic crystal grains. The perpendicular magnetic recording medium has a nonmagnetic underlayer composed of a metal or alloy having hexagonal closest-packed crystal structure. The ferromagnetic crystal grain is composed of an alloy containing at least cobalt and platinum. The volume proportion of the nonmagnetic grain boundary region mainly of the oxide falls within a range of 15% to 40% of the volume of the total magnetic layer.

Abstract: A magnetic recording medium, and method of manufacturing the same, is provided with excellent recording performance by employing a granular magnetic layer having a specified composition. A magnetic recording medium according to the present invention comprises a nonmagnetic underlayer, a granular magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on a nonmagnetic substrate. The granular magnetic layer consists of ferromagnetic crystal grains containing cobalt and nonmagnetic grain boundary region surrounding the ferromagnetic crystal grains. The ferromagnetic crystal grains contain platinum in the range of 15 at % to 17 at %.

Abstract: A perpendicular magnetic recording medium has a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on the substrate. The nonmagnetic layer is composed of a metal or alloy having a hcp crystal structure. The magnetic recording layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary phase mainly composed of an oxide surrounding the grains. A seed layer of a metal or alloy having a fcc crystal structure can be provided under the nonmagnetic underlayer, and a nonmagnetic alignment control layer can be provided under the seed layer. The recording medium can provide high output and low noise by improving the alignment of the magnetic recording layer, reducing the initial growth layer in the magnetic recording layer, and minimizing the grain size of the magnetic recording layer.

Abstract: In a longitudinal magnetic recording medium and a method to manufacture the medium, employing a granular magnetic layer minimizes magnetic particles, resistance to thermal fluctuation is superior, and as a result, SNR is enhanced. The longitudinal magnetic recording medium includes a nonmagnetic underlayer, a nonmagnetic intermediate layer, a magnetic stabilizing layer, a nonmagnetic metallic spacer layer, a magnetic layer, a protective film layer, and a liquid lubricant layer, which are sequentially laminated on a nonmagnetic substrate. The magnetic layer has a granular structure including ferromagnetic crystal grains with a hexagonal closest packed structure and a nonmagnetic grain boundary region surrounding the grains and including an oxide. The stabilizing layer and the magnetic layer are antiferromagnetically coupled to one another through the spacer layer.

Abstract: A magnetic recording medium according to the invention includes a plastic substrate, a non-magnetic under-layer on the substrate, a magnetic layer including cobalt on the under-layer, a protective film on the magnetic layer, and a liquid lubricant layer on the protective film. The under-layer is composed of a chromium alloy having a body centered cubic lattice structure, and containing at least one element selected from the group consisting of Zr, Nb, Mo, Ru and Pd in a total amount of at least 15 at %, or containing at least one element selected from the group consisting of Hf, Ta, W, Re, Pt and Au in a total amount of at least 10 at %. The amount of cobalt dissolved out of the magnetic layer is limited by performing sputtering deposition of at least the magnetic layer at low pressures of argon.

Abstract: A magnetic recording medium has a nonmagnetic substrate, a nonmagnetic underlayer containing at least one metal selected from Ru, Os, and Re laminated on the substrate, and a magnetic layer including ferromagnetic crystal grains and nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains laminated on the underlayer. The underlayer is deposited in a gas atmosphere containing argon and at least one of krypton and xenon in an amount sufficient to reduce the argon remaining in the underlayer to less than 1,000 ppm. Such a gas atmosphere contains at least 10% of krypton or xenon, and pressurized to a range of 30-70 mTorr. The underlayer is formed having film structure composed of fine particles, which is suitable for controlling the structure of the magnetic layer.

Abstract: For protecting a copyright, stored digital information on a recording medium is attenuated in a certain period of time. For this purpose, the thickness of a magnetic layer and the diameter of magnetic crystal grain are changed to control the effect of the thermal oscillation on magnetization of a crystalline region to thereby provide the recording medium with digital information retained for a certain period of time, and attenuated along with time.

Abstract: A magnetic recording medium and manufacture method therefore and magnetic recording apparatus include a nonmagnetic base layer, a nonmagnetic intermediate layer, and a magnetic layer. The nonmagnetic base layer, the nonmagnetic intermediate layer, and the magnetic layer are sequentially stacked on a nonmagnetic substrate to control a partial pressure of H2O in an Ar atmosphere during film formation to make crystal grains of the magnetic layer finer, to obtain a uniform grain size, and to exhibit ferromagnetism and a nonmagnetic grain boundary surrounding the fine crystal grains.

Abstract: A magnetic recording medium and a manufacturing method therefore includes a protective film, a nonmagnetic substrate, a nonmagnetic base layer, a nonmagnetic intermediate layer, a magnetic layer, and a liquid lubricant layer. The nonmagnetic base layer has a body-centered cubic structure and a (200) plane including a crystal-orientation parallel with a surface of the protective film. The nonmagnetic intermediate layer has a hexagonal close-packed structure and a (110) plane including a crystal-orientation parallel with the surface of the protective film. The magnetic layer has a granular structure including hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains. The nonmagnetic base layer, the nonmagnetic intermediate layer, the magnetic layer, the protective film, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate.

Abstract: A perpendicular magnetic recording medium has a granular magnetic layer and a nonmagnetic underlayer of a metal or an alloy having a hexagonal closest-packed (hcp) crystal structure. A seed layer of a metal or an alloy of a face-centered cubic (fcc) crystal structure is provided under the nonmagnetic underlayer. Such a perpendicular magnetic recording medium exhibits excellent magnetic characteristics even when the thickness of the underlayer or the total thickness of the underlayer and the seed layer is very thin. Excellent magnetic characteristics can be obtained even when of the substrate is not preheated. Accordingly, a nonmagnetic substrate, such as a plastic resin can be employed to reduce the manufacturing cost.

Abstract: A perpendicular magnetic recording medium has a magnetic recording layer consisting of two layers. The first magnetic layer, which is a lower layer, comprises crystal grains of a ferromagnetic Co—Cr alloy system and nonmagnetic grain boundaries mainly composed of oxide or nitride, and a thickness a of the first magnetic layer is from 10 nm to 30 nm. The second magnetic layer, which is an upper layer, comprises an amorphous alloy film composed of rare earth element—transition metal alloy, and a thickness b of the second magnetic layer is from 2 nm to 15 nm. The ratio a/b of the thickness a of the first magnetic layer and the thickness b of the second magnetic layer is at least two.

Abstract: A perpendicular magnetic recording medium has a nonmagnetic substrate having concave portions and a soft magnetic layer on the nonmagnetic substrate. The depth of the concave portion and the thickness of the soft magnetic layer are larger than at least the length and the width of the concave portion such that the easy axis of magnetization in the regions of the soft magnetic layer in the concave portions is oriented perpendicular to the soft magnetic layer due to shape magnetic anisotropy. The easy axis of magnetization oriented perpendicular to the soft magnetic layer facilitates signal generation. The recording medium does not use the magnetization of the magnetic recording layer for such signal generation, which can be head positioning signals or other signals, such as copyright data. Instead, it uses the magnetization in the concave regions of the soft magnetic layer for such signal generation.

Abstract: A perpendicular magnetic recording medium and method thereof, includes a nonmagnetic substrate; a soft magnetic under layer; an intermediate layer; a bilayer magnetic recording layer; a protective layer; and a liquid lubricant layer. According to a following order, the soft magnetic under layer, the intermediate layer, the bilayer magnetic recording layer, the protective layer, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate. The bilayer magnetic recording layer includes a first magnetic layer including a CoCr alloy crystalline film, and a second magnetic layer including a rare earth-transition metal alloy noncrystalline film.

Abstract: A magnetic recording medium exhibits a high coercive force and suppresses noises caused therefrom at a low level. The magnetic recording medium includes a nonmagnetic substrate, a nonmagnetic undercoating layer on the substrate where the undercoating layer has a hexagonal close packing structure or a combination of the hexagonal close packing structure and a body center cubic structure. The magnetic recording medium includes a nonmagnetic intermediate layer on the undercoating layer, where the intermediate layer has a hexagonal close packing structure or a combination of the hexagonal close packing structure and a body center cubic structure, and a magnetic layer on the intermediate layer. The magnetic layer has a granular structure formed of ferromagnetic crystal grains and oxide grain boundaries or nitride grain boundaries surrounding the ferromagnetic crystal grains.

Abstract: A magnetic recording medium has at least a non-magnetic under-layer, a magnetic layer, a protective layer and a liquid lubricant layer sequentially laminated on a non-magnetic substrate. The magnetic layer includes ferromagnetic grains and non-magnetic grain boundaries formed of metallic oxide or carbide surrounding the ferromagnetic grains. A non-magnetic intermediate layer, having grains of non-magnetic substance and non-magnetic grain boundaries, formed of metallic oxide or carbide, surrounding the grains of non-magnetic substance, is provided between the non-magnetic under-layer and the magnetic layer. The resulting magnetic recording medium exhibits a high coercive force, Hc, and low noise. Furthermore, the resulting magnetic recording medium prevents the deterioration of the media characteristics in an initial growth region in the granular magnetic layer.

Abstract: A magnetic recording medium has a non-magnetic under-layer, a magnetic layer, a protective film and a liquid lubricant layer sequentially laminated on a non-magnetic substrate. The magnetic layer has a multi-layer structure laminated with two or more magnetic layer components, each of the magnetic layer components having ferromagnetic grains and non-magnetic grain boundaries surrounding the grain. The resulting magnetic recording medium has a granular magnetic layer exhibiting very high Hc accompanying high density of magnetic recording, while decreasing the amount of platinum needed for attaining the high Hc, and reducing media noise accompanying the high recording density.