Various apparatuses, systems, methods, and media are disclosed to provide a magnetic recording medium that capping layer doped with an effective amount of metal to control grain-to-grain exchange coupling in a capping layer. A magnetic recording medium includes a substrate, a magnetic recording layer (MRL) on the substrate, and a capping layer on the MRL. The capping layer include Co and is doped with a metal (e.g., Ru or Ta) in a range from 1 atomic percent to 5 atomic percent, inclusive.

Magnetic media including a magnetic recording layer structure formed of alternating magnetic recording sublayers and non-magnetic exchange control sublayers. The magnetic recording layer structure may include at least one magnetic recording sublayer formed to include a pair of thin films, with the films having different concentrations of platinum, ruthenium, and/or oxide segregants. That is, the sublayer has a “dual layer” structure. The dual layer structure can provide a gradient in magnetic anisotropy, saturation magnetization, and/or intergranular magnetic exchange coupling across the sublayer. In some examples, the film nearer to the substrate of the magnetic media has a higher platinum concentration than the other film. In one aspect, the magnetic media includes the substrate and the magnetic recording layer structure on the substrate, with the structure including six magnetic recording sublayers. In another aspect, a method of fabricating magnetic media with such structures is provided.

Disks for use in hard disk drives (HDD) or other magnetic recording apparatus. The disks are configured based on a finding that internal stress within a disk can make the disk more resistant to shock forces. In one example, a disk is provided that has a substrate with a thickness of no more than 0.5 millimeters and an internal stress no less than 300 megapascals. The relatively high internal stress within the substrate of the disk serves to reduce the magnitude of deflections caused by mechanical shocks to an HDD in which the disk is installed, as compared to other disks of equal thickness but with relatively less internal stress. Multi-platter stacks of the disks are described. Methods are also described for fabricating such disks and for rejecting disks that do not meet certain internal stress-based criteria. Substrates are also described.

Disks for use in hard disk drives (HDD) or other magnetic recording apparatus. The disks are configured based on a finding that internal stress within a disk can make the disk more resistant to shock forces. In one example, a disk is provided that has a substrate with a thickness of no more than 0.5 millimeters and an internal stress no less than 300 megapascals. The relatively high internal stress within the substrate of the disk serves to reduce the magnitude of deflections caused by mechanical shocks to an HDD in which the disk is installed, as compared to other disks of equal thickness but with relatively less internal stress. Multi-platter stacks of the disks are described. Methods are also described for fabricating such disks and for rejecting disks that do not meet certain internal stress-based criteria. Substrates are also described.

The magnetic recording medium includes a non-magnetic support; and a magnetic layer containing a ferromagnetic powder, in which the magnetic layer includes an abrasive, the abrasive is a carbide, an average primary particle diameter of the abrasive is 10 nm or more and 100 nm or less, and in an electron microscope image of a surface of the magnetic layer, assuming that a total area occupied by the abrasive is 100%, a ratio of an area occupied by the abrasive present in an aggregated state having a maximum Feret diameter of 0.2 .Math.m or more is 50% or more.

Provided is a magnetic recording medium having a large magnetocrystalline anisotropy constant K.sub.u and a high coercivity H.sub.c as well as a sputtering target used for producing such a magnetic recording medium.

A Pt-oxide-based sputtering target consists of 60 vol % or more and less than 100 vol % of a Pt-base alloy phase and more than 0 vol % and 40 vol % or less of an oxide, where the Pt-base alloy phase contains 50 at % or more and 100 at % or less of Pt.

Provided is a magnetic recording medium having a large magnetocrystalline anisotropy constant K.sub.u and a high coercivity H.sub.c as well as a sputtering target used for producing such a magnetic recording medium.

A Pt-oxide-based sputtering target consists of 60 vol % or more and less than 100 vol % of a Pt-base alloy phase and more than 0 vol % and 40 vol % or less of an oxide, where the Pt-base alloy phase contains 50 at % or more and 100 at % or less of Pt.

Provided is a magnetic tape in which a center line average surface roughness Ra measured regarding a surface of a magnetic layer is equal to or smaller than 1.8 nm, logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, a back coating layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed regarding a surface of the back coating layer at a photoelectron take-off angle of 10 degrees is equal to or greater than 35 atom %.

Provided is a magnetic tape in which a center line average surface roughness Ra measured regarding a surface of a magnetic layer is equal to or smaller than 1.8 nm, logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, a back coating layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed regarding a surface of the back coating layer at a photoelectron take-off angle of 10 degrees is equal to or greater than 35 atom %.

The magnetic recording medium includes at least a nonmagnetic substrate and a magnetic recording layer, the magnetic recording layer consists of a first magnetic recording layer or a plurality of layers including at least the first magnetic recording layer and a second magnetic recording layer, the first magnetic recording layer has a granular structure including a first magnetic crystal grain and a first nonmagnetic crystal grain boundary, the first magnetic crystal grain consists of an ordered alloy having Fe, Pt and Rh, the first nonmagnetic crystal grain boundary consists of carbon, boron or a combination thereof, the second magnetic recording layer has a granular structure including a second magnetic crystal grain and a second nonmagnetic crystal grain boundary, the second magnetic crystal grain consists of an FePt ordered alloy or an ordered alloy having Fe, Pt and Rh, and the second nonmagnetic crystal grain boundary includes carbon.