Abstract: A perpendicular magnetic recording medium includes a nonmagnetic substrate, and a soft magnetic layer, a first orientation control layer, a second orientation control layer, a nonmagnetic intermediate layer, a magnetic recording layer, and a protective layer layered sequentially on the nonmagnetic substrate. The first orientation control layer includes a thin film having a face-centered cubic (fcc) structure. The magnetic recording layer includes a thin film layer having ferromagnetic crystal grains and nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains, the ferromagnetic crystal grains including a CoPt alloy having ferromagnetic properties, and the nonmagnetic grain boundaries including an oxide or a nitride. The nonmagnetic intermediate layer includes a thin film containing Ru.

Abstract: A perpendicular magnetic recording medium, which includes a nonmagnetic substrate, and a first underlayer in the form of a soft magnetic under-layer (SUL), a second underlayer, an intermediate layer, a magnetic recording layer, a protective layer, and a lubricant layer sequentially laminated on the nonmagnetic substrate. The SUL has a plurality of SUL layers including a type-A SUL layer, a plurality of type-B SUL layers including at least two adjacent type-B SUL layers, and a nonmagnetic metal spacer layer disposed between the two adjacent type-B SUL layers. The type-A SUL layer may include a material selected from Co, Fe and Ni, a material selected from Cr, V and Ti, and a material selected from W, Zr, Ta and Nb. Each of the type-B SUL layers is in antiferromagnetic coupling, and may include a material selected from Co, Fe and Ni, a material selected from Cr, V and Ti, and a material selected from W, Zr, Ta and Nb.

Abstract: A perpendicular magnetic recording medium exhibits reduced noise and improved performance in such measures as SN ratio, and can realize high magnetic recording densities. In the perpendicular magnetic recording medium, at least a first nonmagnetic intermediate layer, second nonmagnetic intermediate layer, and magnetic recording layer are stacked in order on a nonmagnetic substrate. The first nonmagnetic intermediate layer is formed from a CoCrRuW alloy, and the second nonmagnetic intermediate layer is formed from an Ru-base alloy.

Abstract: A perpendicular magnetic recording medium, which includes a first magnetic recording layer, a second magnetic recording layer, and a third magnetic recording layer disposed sequentially on a nonmagnetic substrate, and a coupling layer formed between the first and second magnetic recording layers. The first, second and third magnetic recording layers have an easy axis of magnetization in a direction perpendicular to a film plane of the nonmagnetic substrate. The first and second magnetic recording layers are ferromagnetically coupled via the coupling layer.

Abstract: A perpendicular magnetic recording medium is disclosed that achieves improved recordability without deteriorating thermal stability by reducing the switching field. A perpendicular magnetic recording medium of the invention has a first magnetic recording layer and a second magnetic recording layer between with is interposed a coupling layer that ferromagnetically couples the two layers. The first and second magnetic recording layers satisfy an inequality Ku1T1>Ku2T2 in the case where Hk1 >Hk2 and an inequality Ku1T1<Ku2T2 in the case where Hk1<Hk2, where Hk1 and Hk2 are anisotropy magnetic fields, Ku1 and Ku2 are uniaxial anisotropy constants, and T1 and T2 are thicknesses of the first magnetic recording layer and the second recording layer, respectively. An exchange coupling energy between the magnetic recording layers is preferably at least 5×10?3 erg/cm2.

Abstract: A perpendicular magnetic recording medium is disclosed in which each magnetic crystal grain in the magnetic recording layer has a multilayer structure and has a configuration like a truncated cone shape, in which the crystal grain of the final layer deposited in the film surface side at the final stage is smaller than the diameter of the crystal grain in the initial layer deposited on the substrate side at the initial stage. The invention improves S/N (signal output to noise ratio) by enhancing signal output and reducing noises. The medium is produced by a simple manufacturing method suitable for mass production, and provides a medium of high recording density by improving recording resolution.

Abstract: A perpendicular magnetic recording medium, which includes a nonmagnetic substrate, and a soft magnetic layer, a first orientation control layer, a nonmagnetic intermediate layer, and a perpendicular magnetic recording layer formed sequentially on the nonmagnetic substrate. The perpendicular magnetic recording medium further includes a second orientation control layer provided between the first orientation control layer and the nonmagnetic intermediate layer. The nonmagnetic intermediate layer has hexagonal close-packed (hcp) structure. The first orientation control layer has a face-centered cubic (fcc) structure. The second orientation control layer includes Co and Cr, and has the hcp structure.

Abstract: A perpendicular type of magnetic recording medium includes a substrate, a soft magnetic underlying section including a plurality of distinct layers soft magnetic material, a recording section, and an intermediate section upon which the recording section is formed. The intermediate section is provided to improve the crystal orientation and impart a desired magnetic characteristic to the recording section. An uppermost one of the layers of soft magnetic material which, of all of the layers of soft magnetic material, is disposed closest to the intermediate section is predisposed to induce the intermediate section to crystallize in a desired way as it is formed. Therefore, the intermediate section may have a minimal thickness and yet achieve a crystallization that is sufficient to control the forming of the recording section.

Abstract: A perpendicular magnetic recording medium includes a soft magnetic backing layer, an underlayer, a nonmagnetic intermediate layer, and a magnetic recording layer sequentially deposited on a nonmagnetic substrate. The underlayer can contain cobalt, nickel, and iron and have an fcc structure and exhibit soft magnetic property. The underlayer preferably contains nickel in a range of 30 to 88 at % and iron in a range of 0.1 to 22 at %. The underlayer can further contain Si, B, Nb, N, Ta, Al, Pd, Cr, or Mo. The nonmagnetic intermediate layer preferably contains at least one element selected from Ru, Re, Pd, Ir, Pt, and Rh. The magnetic recording layer preferably has a granular structure. A seed layer can be further provided between the soft magnetic backing layer and the underlayer.

Abstract: A perpendicular magnetic recording medium includes a nonmagnetic substrate, and a soft magnetic layer, a first orientation control layer, a second orientation control layer, a nonmagnetic intermediate layer, a magnetic recording layer, and a protective layer layered sequentially on the nonmagnetic substrate. The first orientation control layer includes a thin film having a face-centered cubic (fcc) structure. The magnetic recording layer includes a thin film layer having ferromagnetic crystal grains and nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains, the ferromagnetic crystal grains including a CoPt alloy having ferromagnetic properties, and the nonmagnetic grain boundaries including an oxide or a nitride. The nonmagnetic intermediate layer includes a thin film containing Ru.

Abstract: A perpendicular type of magnetic recording medium has a multi-layered recording structure made up of a plurality of ferro-magnetic layers and a non-magnetic layer interposed between the plurality of ferro-magnetic layers, and the perpendicular magnetic anisotropy energy of the lower ferro-magnetic layer is greater than the perpendicular magnetic anisotropy energy of the upper ferro-magnetic layer. Accordingly, the lower ferro-magnetic layer may be easily magnetically reversed by a magnetic field applied during a write operation. Thus, the perpendicular type of magnetic recording medium exhibits an enhanced thermal stability and write-ability.

Abstract: A perpendicular type of magnetic recording medium includes a substrate, a soft magnetic underlying section including a plurality of distinct layers soft magnetic material, a recording section, and an intermediate section upon which the recording section is formed. The intermediate section is provided to improve the crystal orientation and impart a desired magnetic characteristic to the recording section. An uppermost one of the layers of soft magnetic material which, of all of the layers of soft magnetic material, is disposed closest to the intermediate section is predisposed to induce the intermediate section to crystallize in a desired way as it is formed. Therefore, the intermediate section may have a minimal thickness and yet achieve a crystallization that is sufficient to control the forming of the recording section.

Abstract: A perpendicular magnetic recording medium composed of a nonmagnetic substrate having a surface onto which are provided a plurality of layers including, in the order recited, a soft underlayer; a nonmagnetic coupling layer; a hard magnetic pinning layer which is antiferromagnetically coupled to the soft underlayer at ambient temperature via the nonmagnetic coupling layer and which has an axis of easy magnetization which extends in a direction which is perpendicular to that of the surface of the nonmagnetic substrate; a nonmagnetic intermediate layer; and a magnetic recording layer. Such a perpendicular magnetic recording medium has an improved medium performance, with reduced noise originating from the presence of the soft underlayer, and no erasure of recorded magnetization when influenced by an external magnetic field.

Abstract: A perpendicular magnetic recording medium, which includes a first magnetic recording layer, a second magnetic recording layer, and a third magnetic recording layer disposed sequentially on a nonmagnetic substrate, and a coupling layer formed between the first and second magnetic recording layers. The first, second and third magnetic recording layers have an easy axis of magnetization in a direction perpendicular to a film plane of the nonmagnetic substrate. The first and second magnetic recording layers are ferromagnetically coupled via the coupling layer.

Abstract: A perpendicular magnetic recording medium, which includes a nonmagnetic substrate, and a soft magnetic layer, a first orientation control layer, a nonmagnetic intermediate layer, and a perpendicular magnetic recording layer formed sequentially on the nonmagnetic substrate. The perpendicular magnetic recording medium further includes a second orientation control layer provided between the first orientation control layer and the nonmagnetic intermediate layer. The nonmagnetic intermediate layer has hexagonal close-packed (hcp) structure. The first orientation control layer has a face-centered cubic (fcc) structure. The second orientation control layer includes Co and Cr, and has the hcp structure.

Abstract: A perpendicular magnetic recording medium, which includes a nonmagnetic substrate, and a first underlayer in the form of a soft magnetic under-layer (SUL), a second underlayer, an intermediate layer, a magnetic recording layer, a protective layer, and a lubricant layer sequentially laminated on the nonmagnetic substrate. The SUL has a plurality of SUL layers including a type-A SUL layer, a plurality of type-B SUL layers including at least two adjacent type-B SUL layers, and a nonmagnetic metal spacer layer disposed between the two adjacent type-B SUL layers. The type-A SUL layer may include a material selected from Co, Fe and Ni, a material selected from Cr, V and Ti, and a material selected from W, Zr, Ta and Nb. Each of the type-B SUL layers is in antiferromagnetic coupling, and may include a material selected from Co, Fe and Ni, a material selected from Cr, V and Ti, and a material selected from W, Zr, Ta and Nb.

Abstract: A perpendicular magnetic recording medium includes a nonmagnetic substrate; a first underlayer provided on the nonmagnetic substrate; a first nonmagnetic intermediate layer provided on the first underlayer; a second underlayer provided on the first nonmagnetic intermediate layer; a second nonmagnetic intermediate layer provided on the second underlayer; and a magnetic recording layer provided on the second nonmagnetic intermediate layer, wherein the first underlayer comprises a soft magnetic material which has a face-centered cubic structure and which includes at least Ni and Fe, and wherein the second underlayer comprises a soft magnetic material which has a face-centered cubic structure and which includes at least Co.

Abstract: A perpendicular magnetic recording medium is disclosed in which each magnetic crystal grain in the magnetic recording layer has a multilayer structure and has a configuration like a truncated cone shape, in which the crystal grain of the final layer deposited in the film surface side at the final stage is smaller than the diameter of the crystal grain in the initial layer deposited on the substrate side at the initial stage. The invention improves S/N (signal output to noise ratio) by enhancing signal output and reducing noises. The medium is produced by a simple manufacturing method suitable for mass production, and provides a medium of high recording density by improving recording resolution.

Abstract: A perpendicular magnetic recording medium includes a nonmagnetic substrate; a first underlayer provided on the nonmagnetic substrate; a first nonmagnetic intermediate layer provided on the first underlayer; a second underlayer provided on the first nonmagnetic intermediate layer; a second nonmagnetic intermediate layer provided on the second underlayer; and a magnetic recording layer provided on the second nonmagnetic intermediate layer, wherein the first underlayer comprises a soft magnetic material which has a face-centered cubic structure and which includes at least Ni and Fe, and wherein the second underlayer comprises a soft magnetic material which has a face-centered cubic structure and which includes at least Co.

Abstract: A perpendicular magnetic recording medium composed of a nonmagnetic substrate having a surface onto which are provided a plurality of layers including, in the order recited, a soft underlayer; a nonmagnetic coupling layer; a hard magnetic pinning layer which is antiferromagnetically coupled to the soft underlayer at ambient temperature via the nonmagnetic coupling layer and which has an axis of easy magnetization which extends in a direction which is perpendicular to that of the surface of the nonmagnetic substrate; a nonmagnetic intermediate layer; and a magnetic recording layer. Such a perpendicular magnetic recording medium has an improved medium performance, with reduced noise originating from the presence of the soft underlayer, and no erasure of recorded magnetization when influenced by an external magnetic field.