Abstract: A magnetic recording medium including a substrate, a first underlayer provided on the substrate, a first magnetic layer provided on the first underlayer, a nonmagnetic coupling layer provided on the first magnetic layer, and a second magnetic layer provided on the nonmagnetic coupling layer. The first and second magnetic layers are exchange-coupled, and have magnetizations that are mutually antiparallel in a state where no external field is applied to the magnetic recording medium. Additionally, the first underlayer is made of Cr or a Cr alloy each having a bcc crystal structure and including nitrogen, and further wherein the first underlayer has a thickness in a range of 0.5 nm to 6.0 nm.

Abstract: A magnetic recording medium is disclosed that includes a substrate; and an underlayer, a first magnetic layer, a non-magnetic coupling layer, a second magnetic layer, a third magnetic layer, a non-magnetic separation layer, and a fourth magnetic layer stacked in this order on the substrate. The first magnetic layer and the second magnetic layer are antiferromagnetically exchange-coupled, and the second magnetic layer and the third magnetic layer are ferromagnetically exchange-coupled. The third magnetic layer has an anisotropic magnetic field smaller than the anisotropic magnetic field of the second magnetic layer, and has a saturation magnetization greater than the saturation magnetization of the second magnetic layer.

Abstract: A method of producing a magnetic recording medium includes forming a underlayer on a base, and successively forming, on the underlayer, a first magnetic layer, a nonmagnetic coupling layer and a second magnetic layer. The first and second magnetic layers are exchange-coupled via the nonmagnetic coupling layer and have antiparallel magnetizations in a state where no external magnetic field is applied on the magnetic recording medium. The underlayer is made of Cr or a Cr alloy having a bcc crystal structure within an atmosphere including nitrogen gas.

Abstract: A method of producing a magnetic recording medium having a recording layer that is magnetized in a recording direction to record information in the recording layer, includes forming a seed layer made of an amorphous CoW or an amorphous CoW alloy material on a substrate surface, forming an underlayer on the seed layer, and forming the recording layer on the underlayer. The forming of the seed layer includes arranging a target to confront the substrate surface, sputtering with respect to the substrate surface sputtering particles of the target from one of two sides partitioned by a first plane that is formed by the recording direction and a substrate normal which is normal to the substrate surface in a predetermined direction inclined with respect to the substrate normal, and oxidizing a surface of the seed layer on which the underlayer is formed.

Abstract: A method of producing a magnetic recording medium includes forming a underlayer on a base, and successively forming, on the underlayer, a first magnetic layer, a nonmagnetic coupling layer and a second magnetic layer. The first and second magnetic layers are exchange-coupled via the nonmagnetic coupling layer and have antiparallel magnetizations in a state where no external magnetic field is applied on the magnetic recording medium. The underlayer is made of Cr or a Cr alloy having a bcc crystal structure within an atmosphere including nitrogen gas.

Abstract: A method of producing a magnetic recording medium includes forming a underlayer on a base, and successively forming, on the underlayer, a first magnetic layer, a nonmagnetic coupling layer and a second magnetic layer. The first and second magnetic layers are exchange-coupled via the nonmagnetic coupling layer and have antiparallel magnetizations in a state where no external magnetic field is applied on the magnetic recording medium. The underlayer is made of Cr or a Cr alloy having a bcc crystal structure within an atmosphere including nitrogen gas.

Abstract: A magnetic recording medium including a ferromagnetic layer made of a Co-based alloy material, a nonmagnetic coupling layer formed on the ferromagnetic layer and made of Ru or a Ru-based alloy material, and a magnetic recording layer formed on the nonmagnetic coupling layer and made of a Co-based alloy material. The nonmagnetic coupling layer is formed by sputtering in an atmosphere of Ar—N2 mixed gas, so that the nonmagnetic coupling layer contains nitrogen. The partial pressure of nitrogen during the sputtering is set in the range of 6.7×10?3 to 3.7×10?2 Pa.

Abstract: A magnetic recording medium which is thermally stable and produces low media noise. By providing a plurality of intermediate layers made of a CoCr alloy of which saturation magnetic flux densities are controlled within a predetermined range, the magnetic recording medium simultaneously realizes both a high S/Nm and thermal stability.

Abstract: An object of this invention is to provide a magnetic recording medium in which its S/Nm (output/medium noise ratio) is improved. This magnetic recording medium is comprised of a first foundation layer made of alloy material composed of mainly Cr with added B, a second foundation layer made of alloy material in which Mo is mixed in Cr, an intermediate layer made of alloy material composed of mainly Co with added Cr and Ta, a lower magnetic layer and an upper magnetic layer made of alloy material composed of mainly Co with added Cr, Pt, B and a protective film composed of mainly C, these layers being formed in this order from the bottom.

Abstract: A magnetic storage medium includes a magnetic layer of a Co alloy of a system Co—Cr—Pt—B—Cu, wherein the magnetic layer has a thickness t and a remnant magnetic flux density Br satisfying a relationship (t×Br) 2.0 nT·m≦(t×Br)≦7.0 nT·m, wherein the Co alloy contains, in addition to Co, Cr with a concentration &bgr; of 20-26 at % (20 at %≦&bgr;≦26 at %), Pt with a concentration &ggr; of 6-20 at % (6 at %≦&ggr;≦20 at %), B with a concentration &dgr; of 1-7 at % (1 at %≦&dgr;≦7 at %), and Cu with a concentration &egr; of 2-7 at % (2 at %≦&egr;≦7 at %).

Abstract: An object of this invention is to provide a magnetic recording medium in which its S/Nm (output/medium noise ratio) is improved. This magnetic recording medium is comprised of a first foundation layer made of alloy material composed of mainly Cr with added B, a second foundation layer made of alloy material in which Mo is mixed in Cr, an intermediate layer made of alloy material composed of mainly Co with added Cr and Ta, a lower magnetic layer and an upper magnetic layer made of alloy material composed of mainly Co with added Cr, Pt, B and a protective film composed of mainly C, these layers being formed in this order from the bottom.

Abstract: A magnetic recording medium which is thermally stable and produces low media noise. By providing a plurality of intermediate layers made of a CoCr alloy of which saturation magnetic flux densities are controlled within a predetermined range, the magnetic recording medium simultaneously realizes both a high S/Nm and thermal stability.

Abstract: A magnetic storage medium includes a magnetic layer of a Co alloy of a system Co—Cr—Pt—B—Cu, wherein the magnetic layer has a thickness t and a remnant magnetic flux density Br satisfying a relationship (t×Br) 2.0 nT·m≦(t×Br)≦7.0 nT·m, wherein the Co alloy contains, in addition to Co, Cr with a concentration &bgr; of 20-26 at % (20 at %≦&bgr;≦26 at %), Pt with a concentration &ggr; of 6-20 at % (6 at %≦&ggr;≦20 at %), B with a concentration &dgr; of 1-7 at % (1 at %≦&dgr;≦7 at %), and Cu with a concentration &egr; of 2-7 at % (2 at %≦&egr;≦7 at %).