A heat-assisted magnetic recording (HAMR) device is configured to write regions of neutral polarity on a magnetic media during a same pass of the recording head in which other regions are written of positive polarity and negative polarity. The various disclosed write techniques may facilitate creation of “zero state” (substantially net zero polarity) transition zones between each pair of data bits of opposite polarity and/or may facilitate the encoding of three different logical states (e.g., 1, 0, and −1) on the media.

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.

A heat-assisted magnetic recording (HAMR) device is configured to write regions of neutral polarity on a magnetic media during a same pass of the recording head in which other regions are written of positive polarity and negative polarity. The various disclosed write techniques may facilitate creation of “zero state” (substantially net zero polarity) transition zones between each pair of data bits of opposite polarity and/or may facilitate the encoding of three different logical states (e.g., 1, 0, and −1) on the media.

A soft underlayer (SUL) and methods for making an SUL are provided, the SUL having characteristics that make it compatible with the high temperature requirements associated with heat-assisted magnetic recording (HAMR) media growth and writing, e.g., temperatures greater than 500° C. The SUL may have a high crystallization temperature of greater than 450° C. and a high Curie temperature greater than 300° C., for example. Additionally, the SUL can maintain a saturation magnetization value greater than, e.g., 9 kGauss, at such high temperatures, thereby having the ability to remain amorphous at temperatures up to, e.g., 650° C., and exhibiting a relatively flat integrated noise profile from approximately 300° C. to 650° C. Further still, a spacer layer material is chosen such that inter-diffusion does not occur at these high temperatures.

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.

According to one embodiment, a magnetic recording medium includes a substrate, a magnetic recording layer on the substrate, and a first protective layer of carbon formed on the magnetic recording layer by thermal CVD.

A disk drive apparatus determines a pattern of bits of a data signal applied to a magnetic write transducer of a heat-assisted magnetic recording apparatus. The magnetic write transducer applies a magnetic field to a recording medium in response to the data signal. A laser power signal is applied to a laser that heats the recording medium while the magnetic field is applied. The laser power signal is modulated based on the pattern of bits. The modulation reduces differences between track widths of recorded marks having different elapsed time values and/or increases a signal-to-noise ratio of the recorded marks having different elapsed time values.

Systems and methods for adding a cap-layer to magnetic recording media are described. In one embodiment, the method may include depositing a magnetic recording layer over a substrate, depositing an interface layer over the magnetic recording layer, and depositing a carbon overcoat layer over the interface layer. In some cases, sputter deposition is used to deposit at least the interface layer. In some cases, oxygen is used as a background gas of the sputter deposition.

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.

A disk drive apparatus determines a pattern of bits of a data signal applied to a magnetic write transducer of a heat-assisted magnetic recording apparatus. The magnetic write transducer applies a magnetic field to a recording medium in response to the data signal. A laser power signal is applied to a laser that heats the recording medium while the magnetic field is applied. The laser power signal is modulated based on the pattern of bits. The modulation reduces differences between track widths of recorded marks having different elapsed time values and/or increases a signal-to-noise ratio of the recorded marks having different elapsed time values.