A magnetic recording medium includes a layer structure including a magnetic layer, a base layer, and a back layer in this order, in which an average thickness t.sub.T is t.sub.T≤5.5 μm, a dimensional variation Δw in a width direction to tension change in a longitudinal direction is 660 ppm/N≤Δw, and a surface roughness R.sub.abe of the base layer on a side of the back layer is 4.2 nm≤R.sub.abe≤8.5 nm.

A heat-assisted magnetic recording (HAMR) media that has a substrate, a granular magnetic recording layer on the substrate, a carbon overcoat, and a non-magnetic seed layer between the granular magnetic recording layer and the carbon overcoat. The seed layer has a refractive index (n) of no more than 0.5 and an extinction coefficient (k) of at least 1, and a thickness no greater than 10 Angstrom. The seed layer can be at least one of Ag, Au, and Cu.

Various apparatuses, systems, methods, and media are disclosed to provide a magnetic recording medium with a tungsten (W) pre-seed layer. The W pre-seed layer has a higher conductance than a CrTi pre-seed layer with a similar thickness. In one embodiment, the W pre-seed layer is made of about 95 atomic percent or more of W. The W pre-seed layer has lower electrical resistivity than the CrTi pre-seed layer. As a result, the thickness of the W pre-seed layer can be reduced as compared to the thickness of a CrTi pre-seed layer if a similar conductance is to be achieved. The magnetic recording materials deposited on top of the W pre-seed layer with the reduced thickness provide comparable crystallographic orientation and recording performance to those deposited on top of a thicker CrTi pre-seed layer with a similar conductance.

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.

A magnetic recording medium is provided and includes a magnetic layer, a non-magnetic layer, a base layer and a back layer, wherein an average thickness t.sub.T of the magnetic recording medium is t.sub.T≤5.3 a dimensional change amount Δw in a width direction with respect to a change in tension in a longitudinal direction is 700 ppm/N≤Δw, a thickness of the non-magnetic layer is 2.0 μm or less, a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more, and the magnetic layer includes a magnetic powder.

A magnetic recording medium includes a flexible and elongated substrate, a soft magnetic layer having an average thickness of 10 nm or more to 50 nm or less, and a recording layer. The soft magnetic layer is disposed between the substrate and the recording layer, and a difference in Young's modulus between the magnetic recording medium and the substrate in a longitudinal direction of the substrate is 2.4 GPa or more.

A magnetic stack includes a substrate and a soft magnetic underlayer deposited on a top surface of the substrate. A heat sink layer is disposed on top of the soft magnetic underlayer, and an interlayer is deposited on top of the heat sink layer. A non-magnetic seed layer is deposited on top of the interlayer. A magnetic recording structure which includes more than one magnetic recording layer is deposited on the top surface of the non-magnetic seed layer.

A heat-assisted magnetic recording (HAMR) medium has a multilayered or laminated heat-sink structure. The laminated heat-sink structure includes a first heat-sink layer and a RuAl—X thermal barrier layer between the medium substrate and the first heat-sink layer. The laminated heat-sink structure may include a second heat-sink layer may between the substrate and the RuAl—X thermal barrier layer. In the RuAl—X thermal barrier layer, X is selected from C and one or more oxides of Si, Ti, W, Zr and Hf. The HAMR medium with the laminated heat-sink structure reduces the amount of required laser current as compared to a similar HAMR medium with a conventional single heat-sink layer of the same thickness, while also slightly improving magnetic properties and recording performance.

The purpose of the present invention is to provide a magnetic recording medium capable of reducing the surface roughness of the magnetic recording layer without adversely affecting the magnetic properties of the magnetic recording layer. The magnetic recording medium of the present invention includes a substrate, a seed layer on the substrate, and a magnetic recording layer on the seed layer, wherein the seed layer has a structure of: (a) a spinel structure consisting of Mg, Cr and O; (b) a spinel structure consisting of Zn, Fe and O; or (c) an inverse spinel structure consisting of Mg, Ti and O.

A magnetic recording cartridge is provided and including a magnetic recording medium, wherein an average thickness of the magnetic recording medium t.sub.T is 3.5 μm≤t.sub.T≤5.6 μm, a dimensional change amount Δw in a width direction of the magnetic recording medium with respect to a tension change in a longitudinal direction of the magnetic recording medium is 700 ppm/N≤Δw≤20000 ppm, the magnetic recording medium is accommodated in a state of being wound around the reel in the cartridge case and (a servo track width on an inner side of winding of the magnetic recording medium)−(a servo track width on an outer side of winding of the magnetic recording medium)>0 is satisfied, and a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more.