Abstract: A magnetic recording media with a multilayer structure and methods for forming the media are described. The magnetic recording media includes a substrate, an underlayer on top of the substrate and a magnetic layer over the underlayer. The underlayer includes a CrN film formed by sputter depositing chromium in the presence of nitrogen or nitrogen containing compounds.

Abstract: The present invention provides a magnetic recording medium comprising an undercoating layer comprising a radiation-curable compound that has been cured by irradiation with radiation, a nonmagnetic layer comprising a nonmagnetic powder and a binder, and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support, wherein the magnetic layer and/or the nonmagnetic layer comprise a carbonic ester denoted by general formula (1), and the undercoating layer has an indentation hardness lower than that of the nonmagnetic support. In general formula (1), each of R1 and R2 independently denotes a saturated hydrocarbon group, with a total number of carbon atoms in R1 and R2 being equal to or higher than 12 but equal to or lower than 50.

Abstract: Epitaxial ferroelectric and magnetic recording structures having graded lattice matching layers are disclosed. A single crystal material such as Si may be used as a substrate material upon which the graded lattice matching layers are deposited. The lattice matching layers may comprise metals and metal alloys, or may comprise oxides doped with selected elements or deposited under different oxygen pressures. A recording layer, such as ferroelectric lead zirconium titanate or a magnetic Fe/Pt multilayer structure, is deposited on the graded lattice matching layers.

Abstract: A thin film structure having a magnetic layer and a seed layer positioned adjacent to the magnetic layer is provided. The seed layer includes a L10 structure.

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: A longitudinal magnetic recording medium having a high medium S/N, with no problems in view of the overwrite characteristic, excellent in the bit error rate and sufficiently stable also to thermal fluctuations is provided. In one embodiment, a first underlayer, second underlayer, and a third underlayer are formed on a substrate and, further, a first magnetic layer, a spacer layer including Ru as a main ingredient, a second magnetic layer, and a third magnetic layer are formed in adjacent with each other in this order. The thickness of the second magnetic layer is made larger than the thickness of the third magnetic layer and the total for the concentrations of cobalt and platinum obtained in the second magnetic layer is not more than the total for the concentrations of cobalt and platinum contained in the third magnetic layer.

Abstract: Embodiments of the present invention provide a magnetic recording medium for use in high-reliable magnetic recording apparatus capable of reading/writing information with high density. In one embodiment, a magnetic recording apparatus includes a magnetic recording medium, a driver for driving the medium in a recording direction, a compound type magnetic head having an electromagnetic induction type magnetic head for recording and a spin-valve type magnetic head for reading in combination, a mechanism to move the head relative to the medium, and a read/write signal processing module for the head. The magnetic recording medium has a magnetic layer formed by way of a first underlayer, a second underlayer and a third underlayer on a substrate.

Abstract: A method of plating on a glass substrate allowing an electroless plating film with good adhesiveness to be formed by chemically bonding a silane coupling agent in a state of simple adhesion or hydrogen bond to the surface of the glass substrate through dehydration condensation reaction, and a method of manufacturing a magnetic recording medium using the plating method. In the plating method, electroless plating is performed on a glass substrate after sequentially conducting at least the adhesion layer formation that forms an adhesion layer using a silane coupling agent solution, catalyst layer formation, a catalyst activation, and a drying that chemically bonds the silane coupling agent in the adhesion layer to the surface of the glass substrate.

Abstract: There is provided a magnetic recording medium formed on an aluminum substrate (Al—Mg alloy), provided with texture striations and a plated layer of NiP, which has magnetic recording medium has magnetic anisotropy in the circumferential direction, and has a high retentivity, a high squareness ratio, and favorable electromagnetic transfer characteristics, a production method thereof, and a magnetic recording and reproducing apparatus. The magnetic recording medium comprises at least an orientation control layer, a nonmagnetic undercoat layer, a magnetic layer, and a protective layer in this order on the aluminum substrate. The orientation control layer contains any one or more component types selected from among Co, Ni, and Fe, and any one or more component types selected from among W, Mo, Ta and Nb.

Abstract: A grain diameter controlling crystalline layer comprising crystalline grains of a metal selected from the group consisting essentially of Cu, Ni, Rh and Pt was formed on a substrate. Then, deposited atom layer of at least one element selected from the group consisting of oxygen and carbon was formed on the surface of the grain diameter control layer. A magnetic recording layer was deposited on the atoms deposited grain diameter controlling crystalline layer. Then a magnetic recording medium in which the magnetic crystalline grains has small grain diameter and small grain diameter distribution, and the magnetic recording medium shows increased signal to noise ratio at high recording density.

Abstract: A process for producing a perpendicular magnetic recording medium comprises forming metallic nuclei or a seed layer on a non-magnetic substrate, and forming a soft magnetic under layer on the metallic nuclei or the seed layer by means of electroless plating. The soft magnetic under layer is formed while an external parallel magnetic field is applied to the non-magnetic substrate, and the substrate is rotated such that the substrate is maintained parallel to the parallel magnetic field.

Abstract: A magnetic recording medium includes a seed layer made of one of AlRu and AlV, a magnetic recording layer made of a CoCr alloy, and an underlayer made of the other of AlRu and AlV, where the underlayer is disposed between the seed layer and the magnetic recording layer.

Abstract: The present invention is a production method for a magnetic recording media in which at least a magnetic layer, a protective layer, and a lubricant layer are sequentially layered onto a non-magnetic substrate 1, and non-magnetic substrate 1 is surface treated using a gas activated by plasma generated at around atmospheric pressure. As a result of the present invention, it is possible to produce magnetic recording media with good yield that have few errors and superior head floating properties, by effectively removing foreign material and projections present on the surface of the magnetic recording media.

Abstract: A magnetic recording medium having good corrosion resistance, electromagnetic conversion characteristics and storability is obtained. In a magnetic recording medium including a foundation layer and a magnetic layer having a thickness of 55 nm or less, which is formed by a vacuum thin film forming technique, on one principal surface of an elongate non-magnetic substrate, the foundation layer is made of a silicon nitride film having a thickness of 2 nm to 50 nm. A magneto-resistive magnetic head or a giant magneto-resistive magnetic head is slid on the magnetic recording medium so as to record and reproduce signals.

Abstract: A magnetic recording medium having good corrosion resistance, electromagnetic conversion characteristics and storability is obtained. In a magnetic recording medium including a foundation layer and a magnetic layer having a thickness of 55 nm or less, which is formed by a vacuum thin film forming technique, on one principal surface of an elongate non-magnetic substrate, the foundation layer is made of a silicon nitride film having a thickness of 2 nm to 50 nm. A magneto-resistive magnetic head or a giant magneto-resistive magnetic head is slid on the magnetic recording medium so as to record and reproduce signals.

Abstract: A perpendicular magnetic recording medium having a substrate, a soft magnetic buffer layer formed on the substrate, an Ru/Ru alloy underlayer formed on the soft magnetic buffer layer, the Ru/Ru alloy underlayer including Ru or a Ru alloy, a recording layer formed on the Ru/Ru alloy underlayer, the recording layer including at least a layer including a plurality of magnetic particles having an easy axis oriented perpendicular to the substrate, and a non-magnetic material surrounding the plural magnetic particles, and a layered structure interposed between the soft magnetic buffer layer and the Ru/Ru alloy underlayer, the layered structure including at least an Ru/Ru alloy crystalline structure film including Ru or a Ru alloy, a first polycrystalline film including Ru or a Ru alloy, and a second polycrystalline film.

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 magnetic recording medium is provided, comprising a substrate, a hexagonal close-packed seedlayer deposited over the substrate, a hexagonal close-packed underlayer deposited over the seedlayer, and a hexagonal close-packed recording layer deposited over the underlayer. The seedlayer is comprised of a ceramic. A method of manufacturing a magnetic recording medium is also provided, comprising the steps of sputtering a first sputter target to deposit a hexagonal close-packed seedlayer over a substrate, sputtering a second sputter target to deposit a hexagonal close-packed underlayer over the seedlayer, and sputtering a third sputter target to deposit a hexagonal close-packed magnetic recording layer over the underlayer. The seedlayer comprises a ceramic.

Abstract: According to an aspect of an embodiment, a magnetic recording medium includes a soft under layer, a seed layer containing an alloy, placed over the soft under layer, a ruthenium containing layer containing crystalline Ru, directly placed on the seed layer, and a recording layer placed over the ruthenium containing layer. The alloy contains metal atoms bonded to one another with a minimum distance of adjacent atoms. The difference between the minimum distance of the atoms in the alloy and that of the atoms in the crystalline Ru is 2% or less.

Abstract: Disclosed is a perpendicular magnetic recording medium including: a nonmagnetic substrate; a first underlayer formed on the nonmagnetic substrate, mainly composed of at least two kinds selected from a group consisting of Fe2O3, Co3O4, MgO, MoO3, Mn3O4, SiO2, Al2O3, TiO2, and ZrO2, and having crystal grains growing in a columnar shape and crystal grain boundaries surrounding the crystal grains; a nonmagnetic second underlayer formed on the first underlayer and having crystal grains with one of a face-centered cubic structure and a hexagonal close-packed structure growing on the crystal grains of the first underlayer; a magnetic layer formed on the second underlayer; and a protective film formed on the magnetic layer.

Abstract: Perpendicular magnetic recording media and methods of fabricating perpendicular magnetic recording media are described. The perpendicular magnetic recording medium of one embodiment includes an interlayer, an underlayer, and a perpendicular magnetic recording layer. The interlayer is formed from a NiWCr alloy.

Abstract: An antiferromagnetically coupled (AFC) magnetic recording medium with an AFC master layer comprising at least two magnetic layers with the top magnetic layer including copper is described. The slave layer is separated from the master layer structure by a nonmagnetic spacer layer selected to antiferromagnetically couple the layers. The master layer structure according to the invention includes a bottom and top layer of distinct ferromagnetic materials. Preferably, the top layer of the master layer is a cobalt alloy including from 1 to 5 at. % copper with an example being CoPt13Cr20B8Cu2. The AFC magnetic layer structure can be used with a variety of substrates including circumferentially textured glass and NiP/AlMg.

Abstract: There is disclosed a magnetic recording medium in which a seed layer, under layer, intermediate layer, first magnetic layer, nonmagnetic layer, second magnetic layer, protective layer, and lubricant layer are successively laminated on a glass substrate, the nonmagnetic layer is constituted of an alloy containing Cr and C, and the magnetic layer is constituted of an alloy containing Co and Pt. The under layer includes at least the seed layer for finely dividing the crystal particles of the magnetic layer, the seed layer includes at least two or more layers of nonmagnetic films, and the intermediate layer formed of the material different from that of the nonmagnetic film is interposed between the nonmagnetic films. In measurement of the thermal stability of the magnetic recording medium, a head is used, the head includes a read/write element, and a write track width is twice or more as large as a read track width in the head.

Abstract: A perpendicular magnetic recording medium includes a substrate, a first underlayer formed over the substrate and formed of ruthenium or a ruthenium alloy with crystal grains growing approximately perpendicular to the substrate and isolated from one another in an in-plane direction by a first air gap, a recording layer placed over the first underlayer and formed of magnetic crystal grains growing approximately perpendicular to the substrate and isolated one another in the in-plane direction by a second air gap, and a grain size dispersion preventing layer inserted between the recording layer and the first underlayer, the grain size dispersion preventing layer including crystal grains of a cobalt-based alloy growing approximately perpendicular to the substrate and an oxide isolating the crystal grains of the cobalt-based alloy from one another in the in-plane direction.

Abstract: In a magnetic recording medium which is able to cope with a higher recording density, there is provided a magnetic recording medium which has a higher coercive force and a lower noise, a production method thereof, and a magnetic recording and reproducing apparatus. The magnetic recording medium is characterized in that at least a nonmagnetic undercoat layer, a nonmagnetic intermediate layer, a magnetic layer, and a protective layer are laminated in this order on a nonmagnetic substrate, and at least one of the layers of the nonmagnetic undercoat layer is constituted by a WV type multicomponent body-centered cubic crystal alloy.

Abstract: The invention provides a magnetic recording medium having a structure in which a magnetic layer containing magnetic particles and a binder is formed on a nonmagnetic layer containing nonmagnetic particles and a binder, wherein the binder contained in the nonmagnetic layer contains a polyurethane resin which has a metal sulfonate group and unsaturated hydrocarbon groups in its molecule and is obtained by reacting a polyester polyol (A) containing an aliphatic dicarboxylic acid as an acid component, an aromatic polyisocyanate compound (B), a compound (C) having unsaturated hydrocarbon groups and a functional group which reacts with an isocyanate group and a molecular weight of 500 or less with a branched compound (D) represented by the following formula (1), and the nonmagnetic layer has good dispersibility even by using fine nonmagnetic particles and can ensure satisfactory coating film strength even at a radiation dose of 3 Mrad or less.

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: A magnetic recording medium is provided which is capable of higher recording density and has a higher coercive force and a lower noise. A production method of the magnetic recording medium, and a magnetic recording and reproducing apparatus are also provided. The magnetic recording medium comprises at least a nonmagnetic undercoat layer, a nonmagnetic intermediate layer, a magnetic layer, and a protective layer, which are laminated in this order on a nonmagnetic substrate, and at least one of the layers of the nonmagnetic undercoat layer is made of a WV alloy or a MoV alloy.

Abstract: The present invention provides a high-capacity magnetic recording medium which has a thinned back coat layer excellent in surface smoothness and durability and is excellent in electromagnetic conversion property. A magnetic recording medium comprising at least a non-magnetic support, a lower non-magnetic layer on one surface of the non-magnetic support, an upper magnetic layer on the lower non-magnetic layer, and a back coat layer on the other surface of the non-magnetic support, wherein the lower non-magnetic layer contains at least carbon black, a non-magnetic inorganic powder other than carbon black, and a binder resin material, the upper magnetic layer contains at least a ferromagnetic powder, and a binder resin material, and the back coat layer contains at least carbon black, a non-magnetic inorganic powder other than carbon black, a phosphate amine salt, and nitrocellulose resin as a binder resin material, and has a thickness of 0.3 to 0.8 ?m.

Abstract: A longitudinal magnetic recording medium includes, in order from a nonmagnetic substrate, a primary coat layer that contains Cr, an intermediate layer, a magnetic layer as a recording layer made of CoCr alloy, and a protective layer, the intermediate layer including a RuCr intermediate layer made of a RuCr alloy that contains 10 to 50 at % of Cr.

Abstract: The various embodiments of the present invention generally relate to the deposition of a seedlayer for a magnetic recording medium used for perpendicular magnetic recording (PMR) applications, where the seedlayer provides for grain size refinement and reduced lattice mis-fit for a subsequently deposited underlayer or granular magnetic layer, and where the seedlayer is deposited using a nickel (Ni) alloy based sputter target. The nickel (Ni) alloy can be binary (Ni—X; Ni—Y) or ternary (Ni—X—Y). In addition, the binary (Ni—X; Ni—Y) or ternary (Ni—X—Y) nickel (Ni) based alloys can be further alloyed with metal oxides, thus forming seedlayer thin films with a granular microstructure containing metallic grains, surrounded by an oxygen rich grain boundary. The nickel-based alloys (with or without metal oxides) of the various exemplary embodiments can be made by powder metallurgical technique or by melt-casting techniques, with or without thermo-mechanical working.

Abstract: A magnetic disk has a soft magnetic underlayer comprising a first layer containing NiFe having a concentration of iron that is at least thirty percent and not more than seventy percent; a second layer that adjoins the first layer and contains FeCoN having a concentration of iron that is greater than the second layer's concentration of cobalt, having a concentration of nitrogen that is less than the second layer's concentration of cobalt and less than three percent; and a third layer containing FeCoNi having a concentration of nickel that is less than eight percent, having a concentration of cobalt that is less than the third layer's concentration of iron and greater than the third layer's concentration of nickel, the third layer adjoining only one of the first and second layers. The first and second layers may be repeated to form a magnetically soft high BS laminate for a disk underlayer.

Abstract: A bit patterned magnetic recording medium comprises a substrate having a surface, and a plurality of spaced apart magnetic elements on the surface, each element constituting a discrete magnetic domain or bit of the same structure and comprised of a stack of thin film layers including in order from the substrate surface: a seed layer; and a perpendicular magnetic recording layer in contact with a surface of the seed layer and comprising a Co1-x-yPtxCry alloy material, where 0.05?x?0.35 and 0?y?0.15. The Co1-x-yPtxCry alloy material has a first order magnetic anisotropy constant K, up to about 2×107 erg/cm3, a saturation magnetization Ms up to about 1200 emu/cm3, an anisotropy field HK=2K1/Ms up to about 35 kOe, a hexagonal (0001) crystal structure with c-axis perpendicular to a surface thereof, and an X-Ray diffraction (XRD) rocking curve with a full width at half maximum (FWHM) of ˜5° or less.

Abstract: A high-recording-density magnetic recording medium and a method of its manufacture can achieve a high OR with only a small reduction in Hcr. The magnetic recording medium has a nonmagnetic substrate and a first seed layer, a second seed layer, a first underlayer, a second underlayer, and a magnetic recording layer formed on the substrate in this order. The first seed layer can be a single layer or a plurality of layers made of at least one material selected from the group consisting of Ni—Ti alloys, Cr—Al alloys, Cr—Ta alloys, and Cr—Ti alloys. The second seed layer can be a single layer or a plurality of layers made of at least one material selected from the group consisting of Ni—W alloys, Ni—Ru—W alloys, and Co—W alloys. The first underlayer can be a single layer or a plurality of layers made of a Cr—Ru alloy. The second underlayer can be a single layer or a plurality of layers made of a Cr alloy comprising Cr and at least one element selected from the group consisting of Mo, B, Ti, and W.

Abstract: There is provided a magnetic recording medium having an extremely thin magnetic layer, in which, not only corrosion of the magnetic layer is suppressed, but also the storage properties and the electromagnetic conversion properties are improved. The magnetic recording medium comprises: an elongated nonmagnetic substrate; a first shielding layer comprised of a metal or an alloy; a second shielding layer comprised of a material which is more hardly oxidized than the first shielding layer, and a magnetic layer, formed by a vacuum thin film formation technique, having a thickness of 55 nm or less. A total thickness of the first shielding layer and the second shielding layer is 2 to 50 nm.

Abstract: A thin film disk for use in magnetic recording with an underlayer structure that includes a layer of CrMoZr, CrMoNb or CrMoMn is described. The preferred embodiment includes a circumferentially textured glass substrate, a pre-seed layer, a B2 seed layer, an underlayer structure and a magnetic layer stack with a plurality of layers. The preferred underlayer structure has a first underlayer of CrTi followed by a second underlayer of CrMoZr. The preferred B2 seed layer material is RuAl. The preferred pre-seed layer is CrTiAl. The preferred magnetic layer stack is CoCr/CoPtCrB/CoPtCrBCu. The preferred embodiment is useful for longitudinal magnetic recording. The in-plane crystallographic orientation, the Mrt orientation ratio and the media SNR are improved by the inclusion of the CrMoZr, CrMoNb or CrMoMn according to the invention.

Abstract: A magnetic recording medium and a magnetic recording medium driving apparatus are disclosed. By providing a plurality of intermediate layers made of a CoCr alloy of which saturation magnetic flux densities are controlled within a predetermined range, the magnetic recording medium, and the magnetic recording medium driving apparatus, realize a high S/Nm and thermal stability.

Abstract: A novel heat assisted magnetic recording (HAMR) medium and the fabrication method therefor are provided. The exchange coupling effect occurring at the interface of FePt/CoTb double layers is adopted, and thus the resulting magnetic flux would be sufficient enough to be detected and readout under the room temperature. The provided HAMR medium exhibits a relatively high saturation magnetization and perpendicular coercivity, and thus possesses a great potential for the ultra-high density recording application.

Abstract: A magnetic recording medium includes a substrate, a magnetic recording layer made of a Co alloy or a CoCr alloy, a seed layer disposed between the substrate and the magnetic recording layer, and an underlayer made of a binary alloy material having a B2 structure and disposed between the seed layer and the magnetic recording layer. The seed layer is made of a material comprising essentially of one of elements forming the binary alloy material of the underlayer.

Abstract: A perpendicular magnetic recording medium including an interlayer structure for crystallographically orienting a layer of a hexagonal close-packed (hcp) perpendicular magnetic recording material formed thereon, comprising in overlying sequence from a surface of a magnetically soft underlayer: (1) a first crystalline layer of a material having a first lattice parameter and a strong preferred growth orientation; (2) a second crystalline layer of a material having a second lattice parameter and the same strong preferred growth orientation as the first crystalline layer; and (3) a third crystalline layer of an hcp material, having a [0002] lattice parameter similar to or different from that of the second lattice parameter of the second crystalline layer and a strong <0002> preferred growth orientation, wherein: the second crystalline layer has a lower interfacial energy with the first crystalline layer and a higher interfacial energy with the third crystalline layer, owing to a lower surface energy of th

Abstract: When a soft magnetic layer for a double layer type perpendicular magnetic recording medium is formed by a plating method, there is the problem of the occurrence of an isolated pulse noise called spike noise so that signal reproduction characteristics are lost. In order to solve this problem, provided are a surface-treated substrate for a magnetic recording medium comprising a substrate having a diameter of not more than 90 mm, and a soft magnetic plating layer comprising an alloy of at least two metals selected from the group consisting of Co, Ni and Fe, which is provided above the substrate, wherein the soft magnetic layer has a coercivity of less than 20 oersted (Oe) in a direction that is parallel to a substrate surface, and wherein a ratio of saturation magnetization to residual magnetization in a direction that is parallel to a surface of the substrate is from 4:1 to 4:3; and a magnetic recording medium comprising the magnetic recording medium substrate.

Abstract: Proposed are a substrate that comprises an easily producible soft magnetic backing film and can reduce spike noise from the soft magnetic backing film, and a method for producing the substrate. More specifically, provided are a substrate for a perpendicular magnetic recording hard disk medium, comprising an Si single crystal substrate (1) having a diameter of 65 mm or less, a thickness of 1 mm or less and an average surface roughness (Rms) of 1 nm or more and 1000 nm or less; an under-plated layer (2) formed on the substrate, the layer (2) comprising one or more metals selected from a group consisting of Ni, Cu and Ag and having a thickness of 1 nm to 300 nm; and a plated soft magnetic layer (3) formed on the under-plated layer, the layer (3) having a thickness of 50 nm or more and less than 1000 nm, a coercivity of 20 Oe(oersteds) or less and a saturation magnetization of 1T or more, wherein the average surface roughness (Rms) of the plated soft magnetic layer is 0.1 nm or more and 5 nm or less.

Abstract: A magnetic recording medium, the order of layers in which is the substrate, the soft underlayer, the seedlayer, the 1st RuCrx-containing interlayer, the 2nd RuCrx-containing interlayer and the magnetic recording layer with preferably a oxides or nitrides-containing magnetic layer comprising grains, is disclosed. High-chromium ruthenium-chromium alloy used as inter layers significantly enhances coercivity and SMNR preferably due to the improved lattice match between RuCr inter layers and CoPt-based magnetic recording layers, and the surface energy of RuCr layers contributes to the performance improvement with the high-chromium addition into Ru inter layers.

Abstract: A magnetic recording medium including a magnetic recording layer and a substrate that supports the magnetic recording layer is provided. At least two underlayers including a nonmetallic underlayer are placed between the magnetic recording layer and the substrate. The perpendicular magnetic recording medium uses a double-layered or tri-layered underlayer. Accordingly, a perpendicular magnetic recording layer can have a high perpendicular magnetic anisotropic energy constant Ku due to a third underlayer and have small crystal grains and a small exchange coupling due to a second underlayer below the third underlayer. Thus, the perpendicular magnetic recording layer can have a good thermal stability, high-density recording characteristics, and excellent SNR characteristics.

Abstract: There is disclosed a magnetic recording medium in which a seed layer, under layer, intermediate layer, first magnetic layer, nonmagnetic layer, second magnetic layer, protective layer, and lubricant layer are successively laminated on a glass substrate, the nonmagnetic layer is constituted of an alloy containing Cr and C, and the magnetic layer is constituted of an alloy containing Co and Pt. The under layer includes at least the seed layer for finely dividing the crystal particles of the magnetic layer, the seed layer includes at least two or more layers of nonmagnetic films, and the intermediate layer formed of the material different from that of the nonmagnetic film is interposed between the nonmagnetic films. In measurement of the thermal stability of the magnetic recording medium, a head is used, the head includes a read/write element, and a write track width is twice or more as large as a read track width in the head.

Abstract: A method for estimating the average intergranular exchange field using measurements of major and minor hysteresis loops. The method also facilitates deshearing hysteresis loops for analysis purposes in perpendicular media. This estimation technique is especially important for modern perpendicular media because exchange plays a critical role and process control can be difficult.

Abstract: A perpendicular magnetic recording medium includes a substrate, an underlayer formed on the substrate, and containing at least one element selected from the group A consisting of Pt, Pd, Rh, Ag, Au, Ir and Fe, and at least one element or compound selected from the group B consisting of C, Ta, Mo, W, Nb, Zr, Hf, V, Mg, Al, Zn, Sn, In, Bi, Pb, Cd, SiO2, MgO, Al2O3, TaC, TiC, TaN, TiN, B2O3, ZrO2, In2O3 and SnO2, and a magnetic layer formed on the underlayer, containing at least one element selected from the group consisting of Fe, Co, and Ni, and at least one element selected from the group consisting of Pt, Pd, Au and Ir, and containing crystal grains having an L10 structure.

Abstract: A magnetic recording medium for perpendicular magnetic recording system includes a nonmagnetic substrate and layers sequentially laminated on the substrate. The layers include a seed layer comprised of a metal or an alloy with a face centered cubic crystal structure, a nonmagnetic underlayer of a metal or an alloy with a hexagonal closest packed crystal structure, a magnetic layer having a granular structure including ferromagnetic crystalline grains with a hexagonal closest packed structure and nonmagnetic grain boundary region of mainly oxide surrounding the crystalline grains, a protective layer, and a liquid lubricant layer.

Abstract: A perpendicular magnetic recording medium, comprising: (a) a non-magnetic substrate having a surface; and (b) a layer stack formed over the substrate surface, comprising in overlying sequence from the substrate surface: (i) a magnetically soft underlayer; (ii) an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material formed thereon; and (iii) at least one crystallographically oriented magnetically hard perpendicular recording layer; wherein the magnetically soft underlayer is sputter-deposited at a sufficiently large target-to-substrate spacing and at a sufficiently low gas pressure selected to provide the underlayer with a smooth surface having a low average surface roughness Ra below about 0.3 nm, as measured by Atomic Force Microscopy (AFM).

Abstract: A magnetic recording medium, a method for producing the same, and a magnetic recording and reproducing device are provided which can prevent spike noise and improve the error rate. The magnetic recording medium comprises at least one nonmagnetic substrate, a soft magnetic underlayer, an orientation control layer to control the orientation of the layer formed directly above the same, and a perpendicular magnetic layer having an axis of easy magnetization which is oriented mainly perpendicularly to the nonmagnetic substrate. The soft magnetic underlayer is formed with a multilayer structure having at least two soft magnetic layers and one or more separation layers interposed between the soft magnetic layers, and at least one of the soft magnetic layers comprises a material with a structure having no magnetic domain walls.