A biaxially orientated polyester film has a P.sub.L/V.sub.L ratio of 0.3 to 1.2, P.sub.L and V.sub.L representing the average diameter of the convex portions and the average diameter of the concave portions, respectively, that are defined on the basis of a slice level with a height of 0 nm (reference plane) in a roughness curve determined for at least one surface using a three dimensional surface roughness meter, and the convex portions accounting for an area ratio of 30% to 51% of the reference plane. The biaxially oriented polyester film is excellent in travelling property, slitting property, and dimensional stability, and serves, when used for magnetic recording medium production, to provide a high density magnetic recording medium having a smooth magnetic layer, suffering little dimensional change due to variations in environmental parameters such as temperature and humidity or due to storage, and having good electromagnetic conversion characteristics with little dropout.

A PMR (perpendicular magnetic recording) head is configured for thermally assisted magnetic recording (TAMR). The thermal energy is supplied by the near-fields of plasmons and the near-fields are directed to a magnetic recording medium by a PPG layer. The PPG layer is Rhodium (Rh) whose small-grained crystal structure normally makes it subject to thermal deformations and other weaknesses. By growing the PPG layer on a thin template layer (TTL), the portion of the PPG layer adjacent to the air-bearing surface (ABS) develops a larger grain size and stronger forces between its atomic constituents which makes it resistant to those deformations.

A PMR (perpendicular magnetic recording) head is configured for thermally assisted magnetic recording (TAMR). The thermal energy is supplied by the near-fields of plasmons and the near-fields are directed to a magnetic recording medium by a PPG layer. The PPG layer is Rhodium (Rh) whose small-grained crystal structure normally makes it subject to thermal deformations and other weaknesses. By growing the PPG layer on a thin template layer (TTL), the portion of the PPG layer adjacent to the air-bearing surface (ABS) develops a larger grain size and stronger forces between its atomic constituents which makes it resistant to those deformations.

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

A multilayer exchange spring recording media consists of a magnetically hard magnetic storage layer strongly exchange coupled to a softer nucleation host. The strong exchange coupling can be through a coupling layer or direct. The hard magnetic storage layer has a strong perpendicular anisotropy. The nucleation host consists of one or more ferromagnetic coupled layers. For a multilayer nucleation host the anisotropy increases from layer to layer. The anisotropy in the softest layer of the nucleation host can be two times smaller than that of the hard magnetic storage layer. The lateral exchange between the grains is small. The nucleation host decreases the coercive field significantly while keeping the energy barrier of the hard layer almost unchanged. The coercive field of the total structure depends on one over number of layers in the nucleation host. The invention proposes a recording media that overcomes the writeability problem of perpendicular recording media.

A magnetic disk used in a hard disk drive device includes a substrate; a magnetic recording layer; and a heat insulating layer provided between the substrate and the magnetic recording layer. Even though a substrate has low heat resistance, as a result of providing the heat insulating layer, the substrate can be used as a substrate for a magnetic disk that can withstand heat treatment (high-temperature annealing).

A multilayer exchange spring recording media consists of a magnetically hard magnetic storage layer strongly exchange coupled to a softer nucleation host. The strong exchange coupling can be through a coupling layer or direct. The hard magnetic storage layer has a strong perpendicular anisotropy. The nucleation host consists of one or more ferromagnetic coupled layers. For a multilayer nucleation host the anisotropy increases from layer to layer. The anisotropy in the softest layer of the nucleation host can be two times smaller than that of the hard magnetic storage layer. The lateral exchange between the grains is small. The nucleation host decreases the coercive field significantly while keeping the energy barrier of the hard layer almost unchanged. The coercive field of the total structure depends on one over number of layers in the nucleation host. The invention proposes a recording media that overcomes the writeability problem of perpendicular recording media.

A multilayer exchange spring recording media consists of a magnetically hard magnetic storage layer strongly exchange coupled to a softer nucleation host. The strong exchange coupling can be through a coupling layer or direct. The hard magnetic storage layer has a strong perpendicular anisotropy. The nucleation host consists of one or more ferromagnetic coupled layers. For a multilayer nucleation host the anisotropy increases from layer to layer. The anisotropy in the softest layer of the nucleation host can be two times smaller than that of the hard magnetic storage layer. The lateral exchange between the grains is small. The nucleation host decreases the coercive field significantly while keeping the energy barrier of the hard layer almost unchanged. The coercive field of the total structure depends on one over number of layers in the nucleation host. The invention proposes a recording media that overcomes the writeability problem of perpendicular recording media.

The invention provides a chemical-mechanical polishing composition comprising (a) an abrasive comprising colloidal silica and fused silica, (b) a compound of formula (I) or a combination of a compound of formula (II) and a hydrophobic organic compound, (c) an amino acid, (d) hydrogen peroxide, and (e) water, wherein the polishing composition has a pH of about 1 to about 5. The invention also provides a method of chemically-mechanically polishing a substrate, especially a nickel-phosphorous substrate, by contacting the substrate with the inventive chemical-mechanical polishing composition.

The magnetic tape device includes a TMR head (servo head); and a magnetic tape, in which a magnetic layer of the magnetic tape includes fatty acid ester, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 7.0 nm, a difference between spacings before and after the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm, and SFD (=SFD.sub.25 C.SFD.sub.# C.) in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50.