Abstract: A perpendicular magnetic recording medium is disclosed in which crystal axis orientation dispersion, crystal grain diameter, and crystal grain diameter dispersion in a magnetic recording layer are reduced. The perpendicular magnetic recording medium has a structure having, stacked sequentially on a non-magnetic substrate, at least an amorphous underlayer, a lower orientation control layer made of Ru or Ru alloy of an hcp structure, an upper orientation control layer that is made of alloy containing an element selected from the group consisting of Co and Ni and an element selected from the group consisting of Cr, W, and Mo and that has an fcc or hcp structure, an intermediate layer, and a magnetic recording layer.

Abstract: A perpendicular magnetic recording medium is disclosed in which crystal axis orientation dispersion, crystal grain diameter, and crystal grain diameter dispersion in a magnetic recording layer are reduced. The perpendicular magnetic recording medium has a structure having, stacked sequentially on a non-magnetic substrate, at least an amorphous underlayer, a lower orientation control layer made of Ru or Ru alloy of an hcp structure, an upper orientation control layer that is made of alloy containing an element selected from the group consisting of Co and Ni and an element selected from the group consisting of Cr, W, and Mo and that has an fcc or hcp structure, an intermediate layer, and a magnetic recording layer.

Abstract: A manufacturing method for a magnetic recording medium is disclosed. By using the method, the anisotropic magnetic field (Hk) of an underlayer is improved, spike noise generated in the soft magnetic underlayer is suppressed, and the signal-to-noise ratio (SNR) is improved without employing a special layer configuration and without the need for complicated and expensive processing. A soft magnetic underlayer is formed by laminating a soft magnetic lower underlayer, a non-magnetic metal layer, and a soft magnetic upper underlayer in succession on a non-magnetic substrate. After forming the non-magnetic metal layer, its surface is exposed to a gas containing between 2 and 100 at % oxygen. A perpendicular magnetic recording layer is formed on the soft magnetic underlayer.

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: A perpendicular magnetic recording medium is disclosed. The formation of a domain wall in a soft magnetic backing layer relative to a large external magnetic field can be suppressed better in the medium, the Hk of the backing layer is improved, and productivity can be increased. The perpendicular magnetic recording medium is formed by laminating at least a soft magnetic backing layer, a non-magnetic underlayer, a magnetic recording layer, and a protective film in succession on a non-magnetic substrate. The backing layer, underlayer, magnetic recording layer, and protective film are formed by a vapor deposition method. The backing layer is a laminated body with a soft magnetic lower backing layer, non-magnetic metal layer, and soft magnetic upper backing layer. The non-magnetic metal layer is formed by forming a metal layer and then subjecting the metal layer to surface exposure processing using a nitrogen-containing gas containing 0.1 to 100 at % nitrogen.

Abstract: A charging current flows through an insulation for insulating two conductors of an electric apparatus by applying an alternate current voltage thereto. A direct current component of the charging current is detected, and is amplified by biasing a direct current voltage to the alternate current voltage. An insulation deterioration of the electric apparatus is determined by an absolute value of the amplified direct current component.

Abstract: A power cable such as a rubber or plastic insulated power cable is diagnosed to be detected an insulation deterioration resulted from water tree generated in an insulation material thereof. At first, charging current flowing from the power cable through a grounding conductor connected to a metal shielding layer thereof to the ground is measured under a state that a rated AC voltage is applied to the power cable. In accordance with the charging current, stray current flowing from the ground to the power cable is calculated. Then, a direct current component of the charging current is detected, and an intrinsic direct current component is calculated by subtracting the stray current from the direct current component. The insulation deterioration is diagnosed in accordance with the level of the intrinsic direct current component.

Abstract: A method for diagnosing an insulation deterioration of a power cable comprising a step of measuring a DC current component in the AC voltage applied to said power cable, by using a filter circuit for cutting off an AC current and a DC current measuring apparatus for measuring small magnitude of DC current. According to the present invention, said filter circuit and said DC current measuring apparatus are joined in parallel each other and connected between a power source and one end portion of said power cable to be diagnosed. The DC current measuring apparatus can detect the polarity, magnitude, and time lapse characteristics of said DC current component for analyzing and estimating the insulation deterioration.

Abstract: A polyolefin insulated electric cable exhibiting the effect of suppressed water tree formation which comprises an electrical insulation layer comprising a polyolefin containing about 0.01 to 13.0% by weight ester groups provided around a conductor.