Certain embodiments are directed to a spin torque oscillator (STO) device in a microwave assisted magnetic recording (MAMR) device. The magnetic recording head includes a seed layer, a spin polarization layer over the seed layer, a spacer layer over the spin polarization layer, and a field generation layer is over the spacer layer. In one embodiment, the seed layer comprises a tantalum alloy layer. In another embodiment, the seed layer comprises a template layer and a damping reduction layer over the template layer. In yet another embodiment, the seed layer comprises a texture reset layer, a template layer on the texture reset layer, and a damping reduction layer on the template layer.

An apparatus comprises a slider configured for heat-assisted magnetic recording comprising an air bearing surface (ABS). The slider comprises a write pole at or near the ABS, and a near-field transducer (NFT) at or near the ABS and proximate the write pole. A main waveguide is configured to receive light from a laser source and communicate the light to the NFT. An optical power sensor comprises a tap waveguide optically coupled to the main waveguide and comprising a first end and an opposing second end. The optical power sensor also comprises a bolometer optically coupled to the tap waveguide and configured to receive a portion of the light extracted from the main waveguide by the tap waveguide.

A recording head includes a near-field transducer proximate a media-facing surface of the recording head and a waveguide that overlaps and delivers light to the near-field transducer. The recording head includes subwavelength-sized focusing mirror comprising first and second reflectors disposed on cross track sides of the near-field transducer. Each of the first and second reflectors is spaced apart from the media-facing surface by a distance, D, measured along an axis normal to the media-facing surface.

A light source-unit includes a laser diode, a sub-mount which the laser diode is joined. The laser diode includes an optical generating layer including an active layer which emits laser-light and cladding layers being formed so as to sandwich the active layer. The active layer includes a quantum dot layer including a plurality of quantum dots, which respectively confine movements of carriers in the three-dimensional directions.

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 magnetic recording medium includes a substrate, an underlayer, and a magnetic layer that are arranged in this order. The magnetic layer has a granular structure including magnetic grains having a L1.sub.0 crystal structure, and grain boundary parts having a volume fraction in a range of 25 volume % to 50 volume %. The magnetic grains have a c-axis orientation with respect to the substrate. The grain boundary parts include a material having a lattice constant in a range of 0.30 nm to 0.36 nm, or in a range of 0.60 nm to 0.72 nm.

An apparatus comprises a slider having an air bearing surface (ABS), a leading edge, and a trailing edge opposing the leading edge. A writer having a write pole is situated at or near the ABS. A near-field transducer (NFT) is situated at or near the ABS and between the write pole and the leading edge of the slider. An optical waveguide is configured to couple light from a laser source to the NFT. A contact sensor is situated between the write pole and the trailing edge. The contact sensor comprises a first ABS section situated at or near the ABS, a second ABS section situated at or near the ABS and spaced apart from the first ABS in a cross-track direction by a gap, and a distal section extending away from the ABS and connecting the first ABS section with the second ABS section.

A data storage device is disclosed comprising a non-energy assist (NEA) head configured to access a first disk surface, and an energy assist (EA) head configured to access a second disk surface. The data storage device further comprises control circuitry configured to write data to the first disk surface, and migrate at least part of the data to the second disk surface.

A near-field transducer or heat sink is formed via a first process. The near-field transducer or heat sink is transfer-printed to a read/write head via a second process.

A recording head comprises a write pole extending to an air-bearing surface. A near-field transducer is positioned proximate a first side of the write pole in a down-track direction. A heatsink structure is proximate the near-field transducer and positioned between the near-field transducer and the write pole. The heatsink structure extends beyond the near-field transducer in a cross-track direction and extends in a direction normal to the air-bearing surface.