Abstract: A magnetic recording medium comprising: a support; and at least a magnetic layer comprising a hexagonal ferrite powder and a binder, wherein the hexagonal ferrite powder is of magnetoplumbite type and has an average diameter of 15 to 35 nm and an alkaline earth element to iron ratio of 0.10 to 0.15 in terms of peak intensity ratio analyzed by electron spectroscopy for chemical analysis.

Abstract: The present invention provides a sputtering target for production of a magnetic recording medium including at least a nonmagnetic undercoat layer, a magnetic layer, and a protective layer laminated sequentially on a nonmagnetic substrate, the sputtering target being used for film formation of the magnetic layer, the sputtering target comprising a mixture of a metal and an oxide, and the particle diameter of the oxide in the sputtering target being 10 &mgr;m or less. The sputtering target suppresses abnormal discharge occurring during film formation of a granular magnetic layer of the magnetic recording medium, and suppresses occurrence of foreign objects on the magnetic recording medium.

Abstract: A magnetic recording medium for reproduction of MR head comprising a support having thereon a substantially non-magnetic low layer and a magnetic layer comprising ferromagnetic hexagonal system ferrite particles dispersed in a binder, in this order, wherein a power spectrum of density at a spatial frequency of 100/mm having frequency-analyzed a surface roughness of the magnetic layer is 10,000 nm3 or less, the power spectrum of density at a spatial frequency of 500/mm is 50 to 500 nm3 and an average tabular diameter of the ferromagnetic hexagonal system ferrite particles is 15 to 35 nm.

Abstract: The present invention pertains to a transparent conductive layered structure having a transparent substrate and a transparent 2-layer film consisting of a transparent conductive layer and a transparent coating layer formed in succession on this substrate, that is used for instance, in the front panel of displays, such as CRTs, etc. The above-mentioned transparent conductive layer has as its main components noble metal microparticles with a mean particle diameter of 1 to 100 nm composed of gold and/or platinum and silver and containing 5 to 95 wt % gold and/or platinum, colored pigment microparticles with a mean particle diameter of 5 to 200 nm, and binder matrix. The noble metal microparticles are mixed at a ratio of 1 to 40 parts by weight per 1 part by weight colored pigment microparticles. Moreover, it is characterized in that the transparent 2-layer film has a surface resistance of 10 to 5000 &OHgr;/□, reflectance of 0 to 2.

Abstract: To avoid troubles associated with high-density recording and fast transfer rate, such as decomposition of lubricant involved in a low floating height magnetic head and migration of lubricants involved in high speed rotation of a magnetic recording medium, and to provide a magnetic recording medium which achieves stable resistance to environment and stable lubricating characteristics, a magnetic recording medium includes a base body and the layers formed on the base body, including a non-magnetic metal underlayer, a magnetic layer, a protective layer, and a lubricant layer. The lubricant of the lubricant layer includes a perfluoropolyether liquid lubricant having an alcohol end group(s) and a perfluoropolyether liquid lubricant having an amine end group(s) of tertiary amine structure.

Abstract: A glass-ceramic substrate for magnetic recording media is textured employing a continuous wave laser light beam to uniformly heat a surface zone, thereby forming a continuously roughened zone defined by recrystallized microcrystals. Embodiments include impinging a continuous wave CO2 laser light beam on a rotating glass-ceramic substrate to uniformly heat an annular zone at a temperature between the crystallization temperature and melting point of the glass-ceramic substrate followed by air cooling to induce a continuous surface roughness having an Ra of about 5 Å to about 20 Å, thereby enabling a glide height of about 0.2 to 0.5 &mgr; in.

Abstract: Provided is a magnetic recording medium suitable for high density digital recording, in detail, a magnetic recording medium suitable for reproduction with an MR head. A magnetic recording medium comprising a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic metal powder, a binder and a nonmagnetic powder provided in this order on a flexible nonmagnetic support. Said magnetic layer has an average thickness ranging from 0.01 to 0.2 &mgr;m, said ferromagnetic metal powder has a mean major axis length of less than 100 nm and a mean minor axis length of less than 20 nm, said nonmagnetic powder comprised in the magnetic layer is a granular or acicular nonmagnetic powder, the ratio of the mean particle size or minor axis length of said nonmagnetic powder to said mean minor axis length is higher than 0.2 and equal to or less than 2.5, and the maximum surface area of magnetic pinholes is equal to or less than 50% of a bit surface area.

Abstract: A magnetic recording disk for thermally-assisted magnetic recording has a low thermal conductivity multilayered thermal barrier between the substrate and the magnetic recording layer to avoid rapid heat conduction away from the locally heated spot and to reduce the amount of power needed to raise the temperature of the recording media above a required value. The barrier comprises a plurality of alternating layers or bilayers of a metal having an electrical resistivity greater than approximately 100 microOhm-cm and a dielectric selected from the group consisting of oxides, nitrides and oxynitrides of one or more of Al and Si. The large number of metal/dielectric interfaces, each with high thermal resistance, reduces the out-of-plane thermal conductivity of the barrier, and the use of high electrical resistivity metal layers minimizes in-plane heat spreading.

Abstract: A magnetic recording medium is provided with a dual layer protective overcoat system comprising a SiC corrosion barrier layer and a carbon-containing protective overcoat thereon. The SiC layer effectively prevents or significantly reduces Co and Ni diffusion to the medium surface. Embodiments include magnetic recording media comprising a SiC corrosion barrier layer over a magnetic layer, an overlying protective layer of amorphous hydrogenated carbon, amorphous nitrogenated carbon or amorphous hydrogen-nitrogenated carbon, and a lubricant topcoat thereon. Embodiments of the present invention further include magnetic recording media comprising Ni—P plated aluminum, Ni-plated glass or non-conductive substrates including glass, glass-ceramic and ceramic materials. Embodiments of the present invention further include a dual protective overcoat system having a combined thickness less than about 100 Å, such as less than about 75 Å, e.g.

Abstract: In a magnetic recording medium, surface roughness of a glass substrate and the variation of the surface roughness are suppressed to the predetermined range. Namely, the surface roughness (Rmax, Ra, Rq) and the relation (Rmax/Ra) between Rmax and Ra are restricted to the predetermined range. In this event, Ra is representative of a center-line mean roughness, Rmax is defined as a maximum height representative of a difference between a highest point and a lowest point and Rq is representative of a root mean square roughness. Thereby, crystal grains of an underlying layer and a magnetic layer formed thereon are equalized. Specifically, the surface roughness is specified by Rmax≦15 nm, Ra≦1 nm and Rq≦1.5 nm. Further, the ratio between the surface roughness Rmax and the surface roughness Ra is specified by Rmax/Ra≦30.

Abstract: A magnetic recording medium using a biaxially oriented aromatic polyamide film as a nonmagnetic support resulting in hardly any improper windings or edge damages. The magnetic recording medium includes a magnetic layer containing ferromagnetic powders dispersed in a binder formed on the nonmagnetic support, wherein the biaxially oriented aromatic support has a ratio of the loss tangent at a temperature of 40° C. to the loss tangent at a temperature of 100° C. of 0.7 or higher.

Abstract: A patterned magnetic recording disk has a magnetic recording layer patterned into discrete magnetic and nonmagnetic regions having substantially the same chemical composition. The magnetic regions have a chemically-ordered L12 crystalline structure and the nonmagnetic regions have a chemically-disordered crystalline structure. The chemically-ordered intermetallic compound CrPt3, which is ferromagnetic, is rendered paramagnetic by ion irradiation. This CrPt3 material is patterned by irradiating local regions through a mask to create nonmagnetic regions. The ions pass through the openings in the mask and impact the chemically-ordered CrPt3 in selected regions corresponding to the pattern of holes in the mask. The ions disrupt the ordering of the Cr and Pt atoms in the unit cell and transform the CrPt3 into paramagnetic regions corresponding to the mask pattern, with the regions of the film not impacted by the ions retaining their chemically-ordered structure.

Abstract: The present invention provides aromatic polyamide resin moldings comprising at least one surface that is 1.0 nm or more in root-mean-square roughness and is 80 nm or less in 10-point average roughness, both of the roughness being as determined by atomic force microscopy, and that is 9.8 GPa or more in tensile Young's modulus at least in one direction. Such aromatic polyamide resin moldings serve effectively as material for film, film for magnetic recording medium in particular, that is highly resistant to scraping and has highly uniform surface protrusions.

Abstract: In a glass substrate for use in a magnetic recording medium, the glass substrate has a pair of principal surfaces opposite to each other and a peripheral side area contiguous to the principal surfaces. The peripheral side area has a side end wall and intermediate regions between the side end wall and the principal surfaces. In this case, at least one of the intermediate regions and the side end wall is formed by a mirror finished surface which has a surface roughness Ra not greater than 1 &mgr;m or a surface roughness Rmax not greater than 4 &mgr;m. With this structure, no particles are generated from the peripheral side area because the side end surface of the glass substrate is mirror finished. Consequently, reproduction is performed without reproduction errors because of no generation of a thermal asperity and a head crash can be sufficiently avoided because of no projections which might result from the particles.

Abstract: Disclosed is a magnetic recording medium excellent in surface properties, good in electromagnetic characteristics, and excellent in durability, which comprises a non-magnetic support and a magnetic layer formed thereon, wherein said magnetic layer contains a ferromagnetic powder, and as binders, at least a vinyl chloride resin having a S-containing polar group and a polyurethane resin having phosphobetaine and/or phosphamine as a polar group.

Abstract: A magnetic recording medium comprising a flexible non-magnetic support, a non-magnetic primer layer containing a binder and non-magnetic particles, formed on the support, and a magnetic layer having a thickness of at most 0.5 &mgr;m and containing a binder and a ferromagnetic acicular metal powder having an average long axis length (L) of at most 0.20 &mgr;m and an aspect ratio (K) of at most 15, formed on the primer layer, wherein the variation (D) of the interface between the magnetic layer and the non-magnetic primer layer is represented by D≦2L/K.

Abstract: A magnetic recording medium including a nonmagnetic support, a lower nonmagnetic layer, and an upper magnetic layer. The nonmagnetic support has a surface. The lower nonmagnetic layer is provided on the surface of the nonmagnetic support. The lower nonmagnetic layer is formed by coating a nonmagnetic coating solution including carbon and a binder. The nonmagnetic coating solution has thixotropy. The upper magnetic layer is provided on the lower nonmagnetic layer and has an average thickness of at most 0.3 .mu.m. The upper magnetic layer includes ferromagnetic powder. A surface roughness of the surface of the nonmagnetic support is limited according to a degree of the thixotropy of the nonmagnetic coating solution.

Abstract: A cleaning medium for magnetic recording devices comprises a non-magnetic substrate, a lower coating layer, which is overlaid upon the non-magnetic substrate and primarily contains a binder and non-magnetic inorganic particles dispersed in the binder, and a cleaning layer, which is overlaid upon the lower coating layer and contains a binder and inorganic particles dispersed in the binder and at least containing ferromagnetic particles. An at least 50% by weight portion of the non-magnetic inorganic particles, which are contained in the lower coating layer, is constituted of granular inorganic particles, which have a mean particle diameter of at most 0.08 .mu.m, or acicular inorganic particles, which have a mean longer axis length falling within the range of 0.05 .mu.m to 0.3 .mu.m and an acicular ratio falling within the range of 3 to 20.

Abstract: In accordance with the present invention, there are provided non-magnetic black particles composed primarily of Fe and having a hematite structure, which shows an excellent blackness, heat resistance, and dispersibility in a vehicle, and which particles contain manganese in an amount of 5 to 40% by weight based on the weight of the non-magnetic black particles, a soluble sodium salt in an amount of not more than 500 ppm (calculated as Na), and a soluble sulfate in an amount of not more than 200 ppm (calculated as SO.sub.4), and have an average particle size of 0.1 to 10.0 .mu.m and a pH of not less than 5.

Abstract: The present invention relates to plate-like ferrite particles with magnetoplumbite structure having a composition represented by the general formula of AO.multidot.n{(Fe.sub.1-(a+b) Bi.sub.a M.sub.b).sub.2 O.sub.3 } wherein A is Ba, Sr or Ba--Sr; M is Zn--Nb, Zn--Ta or Zn--Sn; n is from 5.5 to 6.1; a is from 0.001 to 0.005; b is from 0.050 to 0.120; and the ratio of b/a is from 20 to 50. The plate-like ferrite particles with magnetoplumbite structure have an appropriate particle size, a low coercive force, a large saturation magnetization, a small switching field distribution (S.F.D.) and an excellent temperature stability, and a magnetic card containing the plate-like ferrite particles with magnetoplumbite structure.