Abstract: The problem of the present invention is to provide, in high current-low energy type ion implantation apparatuses, a graphite member for a beam line inner member of an ion implantation apparatus, which graphite member can markedly reduce particles incorporated in a wafer surface. This problem can be solved by the graphite member of the present invention, which is a graphite member for a beam line inner member of an ion implantation apparatus, which member having a bulk density of not less than 1.80 Mg/m3 and an electric resistivity of not more than 9.5 ??·m. Preferably, the R value obtained by dividing D band intensity at 1370 cm?1 by G band intensity at 1570 cm?1 in the Raman spectrum of a spontaneous fracture surface of the graphite member is not more than 0.20.

Abstract: The problem of the present invention is to provide, in high current-low energy type ion implantation apparatuses, a graphite member for a beam line inner member of an ion implantation apparatus, which graphite member can markedly reduce particles incorporated in a wafer surface. This problem can be solved by the graphite member of the present invention, which is a graphite member for a beam line inner member of an ion implantation apparatus, which member having a bulk density of not less than 1.80 Mg/m3 and an electric resistivity of not more than 9.5 ??·m. Preferably, the R value obtained by dividing D band intensity at 1370 cm?1 by G band intensity at 1570 cm?1 in the Raman spectrum of a spontaneous fracture surface of the graphite member is not more than 0.20.

Abstract: Disclosed herein is a substrate for a magnetic disc comprising a glass substrate having fine protrusions on its surface, the protrusions having a height of 50 to 1000 .ANG., a width of 0.01 to 1 .mu.m, a density of 10 to 1000 per 100 .mu.m.sup.2 and an area ratio of 0.1 to 50%, and a ratio of peak height on a mean line (R.sub.p) to maximum height (R.sub.max) with respect to surface roughness of the substrate being at least 60%. Further, a process for preparing the substrate and a magnetic disc having the substrate are disclosed.Because the substrate according to the present invention has appropriate protrusions on its surface, a friction force and an adsorbing force between a head and a magnetic disc can be reduced, leading to the improvement of the CSS and the anti-head stick properties. In addition, the S/N ratio is not affected because the fine concave portions formed on the surface of the substrate are shallow.

Abstract: The lubricant layer according to the present invention is used in a thin film magnetic recording medium in which a solid surface sliding at a high speed is required to retain its lubricating performance and abrasion resistance for a long period of time, comprising a host-guest complex composed of a lubricant molecule as a guest molecule and a multidentate ligand as a host compound to form the complex with the guest molecule.

Abstract: A magnetic recording medium comprising: a non-magnetic substrate;a Co-based alloy magnetic layer (ML); and a non-magnetic Cr-based underlayer position between said magnetic layer and said substrate, compatibly provided with a high S/N and a high coercive force, and an intermediate layer (IL), formed of a Co-based alloy having the hcp structure, which is positioned between the magnetic layer and the non-magnetic underlayer, said intermediate layer having a ratio R=(BsIL*IL)/(BsML*ML), which is the product (BsIL*IL) of the saturation magnetic flux density (BsIL) of the Co-based alloy which constitutes said intermediate layer and the thickness (tIL) of the intermediate layer film to the product (BsML*ML) of the saturation magnetic flux density (BsML) of the Co-based alloy which constitutes said magnetic layer and the magnetic layer film thickness (tML) at 0.2 or less.

Abstract: Disclosed herein is a substrate for a magnetic disc comprising a glass substrate having fine protrusions on its surface, the protrusions having a height of 50 to 1000 .ANG., a width of 0.01 to 1 .mu.m, a density of 10 to 1000 per 100 .mu.m.sup.2 and an area ratio of 0.1 to 50%, and a ratio of peak height on a mean line (R.sub.p) to maximum height (R.sub.max) with respect to surface roughness of the substrate being at least 60%. Further, a process for preparing the substrate and a magnetic disc having the substrate are disclosed. Because the substrate according to the present invention has appropriate protrusions on its surface, a friction force and an adsorbing force between a head and a magnetic disc can be reduced, leading to the improvement of the CSS and the anti-head stick properties. In addition, the S/N ratio is not affected because the fine concave portions formed on the surface of the substrate are shallow.

Abstract: The lubricant layer according to the present invention is used in a thin film magnetic recording medium in which a solid surface sliding at a high speed is required to retain its lubricating performance and abrasion resistance for a long period of time, comprising a host-guest complex composed of a lubricant molecule as a guest molecule and a multidentate ligand as a host compound to form the complex with the guest molecule.

Abstract: A thin-film rigid disk magnetic medium is prepared having a non-magnetic substrate and a magnetic alloy layer formed on the substrate with a non-magnetic underlayer containing chromium as the main component interposed therebetween, where the magnetic alloy layer contains cobalt as the main component and not more than 8 atomic % of boron, not more than 40 atomic % of nickel, not more than 26 atomic % of chromium and not more than 10 atomic % of tantalum. Preferably, the magnetic alloy layer is formed by sputtering while a voltage relatively lower than the plasma potential is applied to the non-magnetic substrate.

Abstract: A magnetic recording medium comprising a non-magnetic substrate and a magnetic alloy layer formed on the substrate with a non-magnetic primer layer containing chromium as the main component interposed therebetween, wherein the magnetic alloy layer contains cobalt and nickel as the main components and not more than 8 atomic % of boron and has been formed by sputtering under such a condition that a negative bias voltage is applied to the non-magnetic substrate.

Abstract: A longitudinal magnetic recording medium comprising a non-magnetic substrate having a texture with a arithmetric average roughness Ra in a circumferential direction of at least 20 .ANG. and a magnetic alloy layer comprising cobalt and chromium as the main components, formed on the substrate, wherein the magnetic alloy layer has (i) a feature that when the orientation degree of the hcp crystal structure is represented by the diffraction ray intensity of electron diffraction by transmission electron diffractiometry, the intensity ratio of the electron diffraction ring in the Co (002) plane between the circumferential direction and the radial direction of the substrate is at least 3, and (ii) a segregation structure having low chromium concentration regions surrounded by high chromium concentration regions, the diameters of the defined low chromium concentration regions being within a range of from 80 to 500 .ANG.

Abstract: A method for producing a magnetic recording medium, which comprises forming, by sputtering, a thin undercoating layer and a thin cobalt alloy magnetic layer sequentially on a substrate, wherein an intermediate electrode is provided in the vicinity of the target to enclose at least 1/2 of the circumference of the sputter erosion end of the target, and at least one of the undercoating layer and the cobalt alloy magnetic layer is formed under such condition that a positive potential relative to the substrate and the grounded portion of the main body of the layer-forming apparatus, is applied to the intermediate electrode.