Overlayers for coating diamond-like carbon (DLC) films are disclosed for use with DLC films employed on the sliders of hard disk drives, such as the sliders of heat assisted magnetic recording (HAMR) or energy assisted magnetic recording (EAMR) drives. In some illustrative examples, the overlayer is formed of an oxide, such as hafnium dioxide or tantalum pentoxide. A buffer layer formed, for example, of silicon nitride is interposed between the oxide overlayer and the DLC film. The oxide layer is provided to prevent oxidation of the DLC film during HAMR so as to maintain thermal stability of the DLC film and prevent a loss of optical transparency at the laser wavelengths of HAMR. The buffer layer is provided to prevent chemical mixing of the oxide overlayer and the DLC film. In other examples, an overlayer formed of silicon nitride is formed directly on the DLC film with no buffer layer.

Methods of forming a layer of magnetic material on a substrate, the method including: configuring a substrate in a chamber; controlling the temperature of the substrate at a substrate temperature, the substrate temperature being at or below about 250 C.; and introducing one or more precursors into the chamber, the one or more precursors including: cobalt (Co), nickel (Ni), iron (Fe), or combinations thereof, wherein the precursors chemically decompose at the substrate temperature, and wherein a layer of magnetic material is formed on the substrate, the magnetic material including at least a portion of the one or more precursors, and the magnetic material having a magnetic flux density of at least about 1 Tesla (T).

The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which an anisotropic magnetic field distribution is 1.20 or less, and the ferromagnetic powder is -iron oxide powder.

According to one embodiment, a manufacturing method of a magnetic recording medium includes measuring characteristics of multilayer film including a magnetic recording layer, calculating a residual between an index value to set a sputtering power and the characteristics, acquiring a feedback correction factor by calculating moving average deviations of the residual, and calculating a new index value of each layer in the multilayer film by using a calculation model which estimates the characteristics from calculated film thicknesses using a virtual metrology technique, referring to the feedback correction factor and performing backward calculation with a solver using an electronic calculator.

The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder, in which an edge portion Ra which is an arithmetic average roughness Ra measured at an edge portion of a surface of the magnetic layer is 1.50 nm or less, a central portion Ra which is an arithmetic average roughness Ra measured at a central portion of the surface of the magnetic layer is 0.30 nm to 1.30 nm, and a Ra ratio (central portion Ra/edge portion Ra) is 0.75 to 0.95.

A magnetic recording medium includes a substrate, an underlayer formed on the substrate, and a magnetic layer formed on the underlayer. The magnetic layer includes an alloy having a L1.sub.0 structure. The underlayer includes a first underlayer and a second underlayer. The first underlayer includes Mo and Ru, the content of Ru in the first underlayer is in a range of 5 atom % to 30 atom %, and the second underlayer includes a material having a body-centered cubic (BCC) structure. The second underlayer is formed between the first underlayer and the substrate.

Disclosed is a perpendicularly magnetized film structure using a highly heat resistant underlayer film on which a cubic or tetragonal perpendicularly magnetized film can grow, comprising a substrate of a cubic single crystal substrate having a (001) plane or a substrate having a cubic oriented film that grows to have the (001) plane; an underlayer formed on the substrate from a thin film of a metal having an hcp structure in which the [0001] direction of the thin metal film forms an angle in the range of 42 to 54 with respect to the <001> direction or the (001) orientation of the substrate; and a perpendicularly magnetized layer located on the metal underlayer and formed from a cubic material selected from a Co-based Heusler alloy and a cobalt-iron (CoFe) alloy having a bcc structure a constituent material, and grown to have the (001) plane.

A heat-assisted magnetic recording (HAMR) disk has a magnetic recording layer (typically a FePt chemically-ordered alloy), a seed-thermal barrier layer (typically MgO) below the recording layer, a heat-sink layer, and an optical-coupling multilayer of alternating plasmonic and non-plasmonic materials between the heat-sink layer and the seed-thermal barrier layer. Unlike a heat sink layer, the multilayer has very low in-plane and out-of-plane thermal conductivity and thus does not function as a heat sink layer. The multilayer's low thermal conductivity allows the multilayer to also function as a thermal barrier. Due to the plasmonic materials in the multilayer it provides excellent optical coupling with the near-field transducer (NFT) of the HAMR disk drive.

An epsilon iron oxide has an average particle size of 10 to 18 nm, a part of the iron element being substituted with a substitutional element and has a coercive force of 14 kOe or less, wherein a coefficient of variation of the particle size is 40% or less. A method for producing the same, a magnetic coating material and a magnetic recording medium using the epsilon iron oxide, includes depositing a metal compound of a substitutional element on iron oxide hydroxide to thereby obtain iron oxide hydroxide on which the metal compound is deposited; coating the iron oxide hydroxide on which the metal compound is deposited, with silicon oxide to thereby obtain iron oxide hydroxide coated with the silicon oxide; and applying heat treatment to the silicon oxide-coated iron oxide hydroxide in an oxidizing atmosphere, wherein a part of an iron element is substituted with the substitutional element.

A heat-assisted magnetic recording (HAMR) medium has a non-magnetic multilayered overcoat on the recording layer. The overcoat includes a heat-dissipation layer, a diamond-like carbon (DLC) layer on and in contact with the heat-dissipation layer, and an optional interface layer between and in contact with the recording layer and the heat-dissipation layer. The heat-dissipation layer is a material with relatively high in-plane thermal conductivity, substantially higher than the in-plane thermal conductivity of both the DLC layer and the recording layer. The heat-dissipation layer laterally spreads the heat generated in the DLC layer by absorption of light from the near-field transducer to thereby reduce the temperature of the DLC layer. The optional interface layer is a material with relatively low thermal conductivity and increases the thermal resistance between the recording layer and the heat-dissipation layer.