There is provided a magnetic recording medium of which an average thickness t.sub.T is t.sub.T5.6 , a dimensional change amount w in a width direction with respect to a change in tension in a longitudinal direction is 660 ppm/Nw, a squareness ratio in a vertical direction is 65% or more, and a width deformation coefficient b during long-term storage in a case where a long-term storage width change amount Y is defined as Y=blog(t) is 0.06 mb0.06 .

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.T5.3 m, a dimensional change amount w in a width direction with respect to a change in tension in a longitudinal direction is 700 ppm/Nw, a thickness of the non-magnetic layer is 2.0 m 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 cartridge includes a magnetic recording medium of which an average thickness t.sub.T is t.sub.T5.6 m, a dimensional change amount w in a width direction with respect to a tension change in a longitudinal direction is 660 ppm/Nw, and a squareness ratio in a vertical direction is 65% or more, in which the magnetic recording medium is accommodated in a state of being wound around a reel 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.

A magnetic recording medium includes a layer structure including a magnetic layer, a non-magnetic layer, and a base layer in this order, in which an average thickness t.sub.T is t.sub.T5.5 m, a dimensional variation w in a width direction to tension change in a longitudinal direction is 660 ppm/Nw, and an average thickness t.sub.n of the non-magnetic layer is t.sub.n1.0 m.

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.T5.5 m, a dimensional variation w in a width direction to tension change in a longitudinal direction is 660 ppm/Nw, and a surface roughness R.sub.abe of the base layer on a side of the back layer is 4.2 nmR.sub.abe8.5 nm.

Large magnetic moment compositions are formed by stabilizing ternary or other alloys with a epitaxial control layer. Compositions that are unstable in bulk specimen are thus stabilized and exhibit magnetic moments that are greater that a Slater-Pauling limit. In one example, Fe.sub.xCo.sub.yMn.sub.z layers are produced on an MgO(001) substrate with an MgO surface serving to control the structure of the Fe.sub.xCo.sub.yMn.sub.z layers. Magnetizations greater than 3 Bohr magnetons are produced.

In a magnetic recording medium, an average thickness t.sub.T is t.sub.T5.5 m, a dimensional variation w in a width direction to tension change in a longitudinal direction is 650 ppm/Nw, and a rate of shrinkage in the longitudinal direction is 0.08% or less.

The present disclosure generally relates to a magnetic media drive employing a magnetic recording head. The head includes a main pole at a media facing surface (MFS), a trailing shield at the MFS, and a MAMR stack disposed between the main pole and the trailing shield at the MFS. The MAMR stack includes a seed layer and at least one magnetic layer. The seed layer is fabricated from a thermally conductive material having electrical resistivity lower than that of the main pole. The seed layer has a stripe height greater than a stripe height of the at least one magnetic layer. With the extended seed layer, the bias current from the trailing shield to the main pole spreads further away from the MFS along the extended seed layer before flowing into the main pole, reducing temperature rise at or near the MAMR stack, leading to improved write head reliability.

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 mt.sub.T5.6 m, a dimensional change amount w 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/Nw20000 ppm, and 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.

A heat assisted magnetic recording disk drive comprises a magnetic recording media with a heat sink layer including at least a material being defined by the general structure M.sub.n+1AX.sub.n, wherein M is a transition metal, A is an A-group element, X is C or N or a mixture of C and N, and n is a positive integer, or a material defined by the general structure M.sub.n+1AX.sub.n, wherein M is a transition metal, X is one or both of C and N, and n is a positive integer, or a mixture of the materials being defined by the general structure M.sub.n+1AX.sub.n and the material defined by the general structure M.sub.n+1X.sub.n, wherein the crystal structure of the materials is hexagonal with repeated M-X-M (quasi 2D) atomic layers. The atomic layers are stacked along the {right arrow over (c)}-axis that is oriented substantially parallel to the surface normal of the heat sink layer.