Abstract: In a magnetic recording medium, a plurality of non-magnetic metallic intermediate layers is laminated between an under-layer and a magnetic layer. One of the intermediate layers is composed of at least an element selected from the group consisting of Ru, Re and Os and contains oxygen, and another is composed of a CoCr alloy containing at least an element selected from the group consisting of Nb, Mo, Ru, Rh, Pd, Ta, W, Re Os, Ir and Pt. The resulting magnetic recording medium provides reduced costs and improved recording characteristics.

Abstract: A magnetic recording medium achieves excellent noise reduction by controlling the crystal orientation of a magnetic layer without thermal processing. The magnetic recording medium includes multiple layers laminated to a substrate. These layers include at least the magnetic layer and a non-magnetic under layer. The magnetic layer has a granular structure consisting of ferromagnetic grains with a hexagonal close-packed structure and non-magnetic grain boundaries composed mainly oxide or a nitride. The non-magnetic under-layer is a material having a body centered cubic crystal structure with a preferential orientation along a (200) plane parallel to a film surface of the under-layer.

Abstract: A manufacturing method achieves excellent magnetic recording characteristics by sequentially sputtering a non-magnetic under-layer, a non-magnetic intermediate layer, and a magnetic layer on a non-magnetic substrate in an atmosphere of H2O partial pressure of 2×10−10 Torr or lower. This process allows beneficial deposition of the magnetic layer and reduces raw materials costs. The magnetic layer includes ferromagnetic grains and non-magnetic grain boundaries. The intermediate layer has a hexagonal close-packed crystal structure. The manufacturing method allows manufacture of a high quality magnetic recording medium without a heating step thereby allowing use of lower cost materials, reduces manufacturing time, and increases savings.

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: The present invention provides a magnetic recording medium including at least a nonmagnetic undercoat layer, a nonmagnetic metallic intermediate layer, a magnetic layer, a protective film, and a liquid lubricant layer sequentially laminated on a nonmagnetic substrate, wherein the magnetic layer contains crystal grains having ferromagnetism and nonmagnetic grain boundaries surrounding the crystal grains, and the nonmagnetic metallic intermediate layer contains at least one layer, and the crystal structure of each layer being a hexagonal close-packed structure; and a method for producing the magnetic recording medium. The magnetic recording medium shows high coercive force Hc and a low medium noise, and its manufacturing cost is also low.

Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.

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 includes an uneven layer, a non-magnetic metal base layer, a magnetic layer and a protective layer which are laminated on a non-magnetic base in the order of description. The uneven layer includes non-magnetic metal deposits containing nitrogen or oxygen, and consists of mutually isolated protrusions having a crystalline phase, which are discretely dispersed on the surface of the non-magnetic base, and a connecting layer having an amorphous phase for filling spaces between the protrusions so as to connect the protrusions with each other.

Abstract: A magnetic recording medium capable of making a high-density recording, with improved magnetic characteristics such as coercive force (Hc) and other factors, in which the flatness of the surface of a magnetic recording medium is maintained, and a method for the manufacture thereof are disclosed. By disposing a non-magnetic metal buffer layer 6 between a non-magnetic glass substrate 1 and a non-magnetic metal under layer 2 and keeping a ratio d.sub.1 /d.sub.2 of the half bandwidth of an X-ray diffraction peak of the metal buffer layer 6 and the metal under layer 2 predetermined values, a large increase in coercive force (Hc) can be obtained. In addition, by controlling the film thickness .delta. of the metal buffer layer 6 and the base substance temperature (T) when the metal buffer layer 6 is formed, magnetic characteristics such as squareness (S), coercive force squareness (S.sup.*), coercive force difference (.DELTA. HC) and coercive force squareness difference (.DELTA. S.sup.*) can be improved.

Abstract: A magnetic recording medium capable of making a high-density recording, with improved magnetic characteristics such as coercive force (Hc) and other factors, in which the flatness of the surface of a magnetic recording medium is maintained, and a method for the manufacture thereof are disclosed; by disposing a non-magnetic metal buffer layer 6 between a non-magnetic glass substrate 1 and a non-magnetic metal under layer 2 and keeping a ratio d.sub.1 /d.sub.2 of the half bandwidth of an X-ray diffraction peak of the metal buffer layer 6 and the metal under layer 2 predetermined values, a large increase in coercive force (Hc) can be obtained; in addition, by controlling the film thickness .delta. of the metal buffer layer 6 and the base substance temperature (T) when the metal buffer layer 6 is formed, magnetic characteristics such as squareness (S), coercive force squareness (S*), coercive force difference (.sub..DELTA. HC) and coercive force squareness difference (.sub..DELTA. S*) can be improved.

Abstract: To improve the sliding characteristics of a magnetic head by reducing a friction coefficient, and realize a magnetic recording medium with a high recording density and a large capacity, capable of reducing the flotation distance of the magnetic head. On the surface of a base, aluminum containing nitrogen aggregates locally to form islands of metal deposits, which are distributed discretely over the entire surface of the base. Meanwhile, on the metal deposits, a metal base layer, a magnetic layer, a protective layer, and a lubrication layer are laminated sequentially to form a magnetic recording disk. On the disk surface, ultrafine irregularities are formed that reflect the shapes of the metal deposits, thereby realizing a reduction in the friction coefficient.

Abstract: A thin-film magnetic head is disclosed that includes a lower magnetic core and an upper magnet core formed on the surface of a substrate and connected together at a first end thereof, a magnetic gap is formed between the lower and upper magnetic cores at a second end thereof, and a coil-form electric conductive layer is located between the lower magnetic core and the upper magnet core. The lower and upper magnetic cores have a saturated magnetic flux density from 10,000 G to 18,000 G, while the magnetic permeability along the magnetic path of the magnetic head is 3,000 or higher at a frequency of 10 MHz. The unique characteristics of the magnetic head are obtained by heating an arrangement comprising the lower and upper magnetic cores, the magnetic gap layer, and the electric conductive layer to a temperature above 325.degree. C., and applying an external magnetic field greater than 0.