A thermally assisted magnetic head including a slider and a light source-unit. The slider includes a slider substrate and a magnetic head part. The light source-unit includes a laser diode and a sub-mount. The magnetic head part includes a medium-opposing surface, a light source-opposing surface and a waveguide which guides laser light from the light source-opposing surface to the medium-opposing surface. The thermally assisted magnetic head includes an optimal-structure which the following optimizing conditional expression, concerning an inlet-optical path length L1 of an inlet-interval of the waveguide, and an outlet-optical path length L2 of an outlet-interval, is satisfied,
m.sub.1L1=L2 (m.sub.1 is a natural number).

Disclosed herein are sliders having air-bearing surface (ABS) designs to mitigate the effects of smear on near-field transducers used in data storage devices, and data storage devices comprising such sliders. A slider comprises a leading edge, a trailing edge, a NFT, and an ABS with features to increase oxygen concentration near the NFT. The ABS comprises a channel configured to direct gas in a direction from the leading edge toward the trailing edge and a funnel region connected to the channel, disposed between the channel and the NFT, and configured to receive gas from the channel. In an ABS view of the slider, a width of the funnel region along a longitudinal axis passing through the NFT monotonically increases with distance from the NFT.

Disclosed herein are sliders having air-bearing surface (ABS) designs to mitigate the effects of smear on near-field transducers used in data storage devices, and data storage devices comprising such sliders. A slider comprises a leading edge, a trailing edge, a NFT, and an ABS with features to increase oxygen concentration near the NFT. The ABS comprises a channel configured to direct gas in a direction from the leading edge toward the trailing edge and a funnel region connected to the channel, disposed between the channel and the NFT, and configured to receive gas from the channel. In an ABS view of the slider, a width of the funnel region along a longitudinal axis passing through the NFT monotonically increases with distance from the NFT.

A heat-assisted magnetic recording medium includes a substrate, an underlayer, and a magnetic layer including an alloy having a L1.sub.0 crystal structure and first and second layers, arranged in this order. Each of the first and second layers has a granular structure including C, SiO.sub.2, and BN at grain boundaries. Vol % of the grain boundaries in each of the first and second layers is 25 to 45 vol %. Vol % of C in the first layer is 5 to 22 vol %, and a volume ratio of SiO.sub.2 with respect to BN in each of the first and second layers is 0.25 to 3.5. Vol % of SiO.sub.2 in the second layer is greater than that of the first layer by 5 vol % or more. Vol % of BN in the second layer is smaller than that in the first layer by 2 vol % or more.

A heat-assisted magnetic recording medium includes a substrate, an underlayer, and a magnetic layer including an alloy having a L1.sub.0 crystal structure and first and second layers, arranged in this order. Each of the first and second layers has a granular structure including C, SiO.sub.2, and BN at grain boundaries. Vol % of the grain boundaries in each of the first and second layers is 25 to 45 vol %. Vol % of C in the first layer is 5 to 22 vol %, and a volume ratio of SiO.sub.2 with respect to BN in each of the first and second layers is 0.25 to 3.5. Vol % of SiO.sub.2 in the second layer is greater than that of the first layer by 5 vol % or more. Vol % of BN in the second layer is smaller than that in the first layer by 2 vol % or more.

Systems and methods for coating a near field transducer in a dielectric material are described. In one embodiment, the method may include forming a liquid solution comprising at least a first dielectric and a disk surface lubricant, forming a coating of the liquid solution on an outer surface of a storage medium based at least in part on dipping the storage medium in the liquid solution, and accumulating a first set of molecules of the first dielectric on a near field transducer (NFT) of a HAMR head based at least in part on evaporating a first portion of the first dielectric in the coating by performing a first HAMR writing operation that shines a laser on the coating.

Systems and methods for coating a near field transducer in a dielectric material are described. In one embodiment, the method may include forming a liquid solution comprising at least a first dielectric and a disk surface lubricant, forming a coating of the liquid solution on an outer surface of a storage medium based at least in part on dipping the storage medium in the liquid solution, and accumulating a first set of molecules of the first dielectric on a near field transducer (NFT) of a HAMR head based at least in part on evaporating a first portion of the first dielectric in the coating by performing a first HAMR writing operation that shines a laser on the coating.

A heat-assisted magnetic recording medium includes a substrate, an underlayer, and a magnetic layer including an alloy having a L1.sub.0 crystal structure and first and second layers, arranged in this order. Each of the first and second layers has a granular structure including C, SiO.sub.2, and BN at grain boundaries. Vol % of the grain boundaries in each of the first and second layers is 25 to 45 vol %. Vol % of C in the first layer is 5 to 22 vol %, and a volume ratio of SiO.sub.2 with respect to BN in each of the first and second layers is 0.25 to 3.5. Vol % of SiO.sub.2 in the second layer is greater than that of the first layer by 5 vol % or more. Vol % of BN in the second layer is smaller than that in the first layer by 2 vol % or more.

A heat-assisted magnetic recording medium includes a substrate, an underlayer, and a magnetic layer including an alloy having a L1.sub.0 crystal structure and first and second layers, arranged in this order. Each of the first and second layers has a granular structure including C, SiO.sub.2, and BN at grain boundaries. Vol % of the grain boundaries in each of the first and second layers is 25 to 45 vol %. Vol % of C in the first layer is 5 to 22 vol %, and a volume ratio of SiO.sub.2 with respect to BN in each of the first and second layers is 0.25 to 3.5. Vol % of SiO.sub.2 in the second layer is greater than that of the first layer by 5 vol % or more. Vol % of BN in the second layer is smaller than that in the first layer by 2 vol % or more.

An apparatus comprises a write pole, a waveguide core, and a near-field transducer (NFT) positioned between the write pole and the waveguide core. The NFT comprises an enlarged portion and a peg comprising a refractory metal and extending from the enlarged portion toward a media-facing surface. A first dielectric layer is positioned between the peg and the write pole, and a first adhesion layer is positioned between the peg and the first dielectric layer. In addition, a second dielectric layer is disposed on an entire surface of the NFT opposing the media-facing surface, and a second adhesion layer is positioned between the NFT and the second dielectric layer.