Techniques for determining a maximum permissible media deposition temperature for depositing one or more layers over a substrate of a heat assisted magnetic recording (HAMR) platform. In one aspect, a method includes controlling a thermomechanical analyzer to measure the mechanical expansion of a glass material versus temperature within a temperature range that is below the primary transformation temperature (Tg) of the glass material to detect a possible initial transformation that occurs within the glass material at a temperature (Tt) below the primary transformation temperature (Tg). If such an initial transformation is detected, the maximum deposition temperature is set based on the initial transformation temperature (Tt), rather than on the primary transformation temperature (Tg). Otherwise, the maximum permissible media deposition temperature is set based on the transformation temperature (Tg). In other aspects, methods for characterizing a glass material for suitability within the substrate of the HAMR platform are provided.

The present disclosure relates to pretreating a magnetic recording head to increase the lifetime of the magnetic media drive. A transparent smear is purposefully formed on the magnetic recording head to ensure the magnetic recording head does not overheat and lead to a short drive lifetime. The transparent smear is formed from material found in the magnetic media. The transparent smear is formed by pretreating the magnetic recording head with the transparent material from the magnetic media. The pretreating occurs without writing any data to the magnetic media. Once the transparent smear is in place, writing may occur. The magnetic recording head can be retreated at a later time should the transparent smear degrade. Furthermore, if an optically absorbing smear develop, it can be removed and a new transparent smear may be formed.

Two or more different elapsed time values are determined between transitions of a data signal applied to a magnetic write transducer of a heat-assisted magnetic recording apparatus. Two or more different power values of the laser are respectively associated with the two or more different elapsed time values. The two or more different power levels are selected to reduce differences between track widths of recorded marks having the two or more different elapsed time values.

A recording device comprising an overcoat layer, wherein the overcoat layer comprises an amorphous carbon overcoat layer having a crystallinity (C)≤0.8.

Systems and methods for treating a carbon overcoat surface are described. In one embodiment, the method may include depositing a magnetic recording layer over a substrate, depositing a carbon overcoat layer over the magnetic recording layer, and exposing a carbon overcoat layer to water in gas phase after the carbon overcoat layer is deposited on the magnetic recording layer. In some cases, the method may include depositing a lubricant over the outer surface of the carbon overcoat after exposing the carbon overcoat layer to the water in gas phase.

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.

The present disclosure relates to pretreating a magnetic recording head to increase the lifetime of the magnetic media drive. A transparent smear is purposefully formed on the magnetic recording head to ensure the magnetic recording head does not overheat and lead to a short drive lifetime. The transparent smear is formed from material found in the magnetic media. The transparent smear is formed by pretreating the magnetic recording head with the transparent material from the magnetic media. The pretreating occurs without writing any data to the magnetic media. Once the transparent smear is in place, writing may occur. The magnetic recording head can be retreated at a later time should the transparent smear degrade. Furthermore, if an optically absorbing smear develop, it can be removed and a new transparent smear may be formed.

A stack comprises a substrate, a magnetic recording layer, and a negative thermal expansion layer disposed between the substrate and the magnetic recording layer. The negative thermal expansion layer is configured to reduce thermal profile changes of a surface of the stack opposite the substrate during a heat assisted magnetic recording write operation.

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.

A magnetic recording medium for microwave-assisted recording, including a non-magnetic support; and a magnetic layer containing a ferromagnetic powder and a binding agent, in which the ferromagnetic powder has an average particle size of 5 nm to 20 nm, and a coefficient of variation of a particle size distribution of 35% or lower, and the magnetic layer has a thickness of 25.0 nm to 100.0 nm, and a thickness variation of 1.0 nm to 12.0 nm. A magnetic recording device including a magnetic recording medium and a magnetic head for microwave-assisted recording. A manufacturing method of a magnetic recording medium having a servo pattern on a magnetic layer.