A heat-assisted magnetic recording (HAMR) disk drive uses a semiconductor laser mounted on a slider to deliver light to a near-field transducer (NFT) via a waveguide located inside the slider. The waveguide includes a core and cladding material that is transparent to the laser light and surrounds the core. Layers of stray light absorption material are located inside the slider on opposite edges of the waveguide core in the same plane as the core and on opposite sides of the waveguide core in planes spaced from the plane of the core. Portions of the waveguide cladding material are located between the waveguide core and the stray light absorption layers. The stray light absorption layers absorb light that leaks into the cladding material and substantially reduces stray light reflected to the laser to prevent undesirable laser power fluctuation.

Example read transducers, data storage devices, and methods to provide an angled free layer for generating and decoding multi-level read signals are described. The read transducer includes a free layer having a magnetization bias sensitive to an external magnetic field and the direction of the magnetization bias forms an acute angle relative to a surface of the non-volatile storage medium generating the external magnetic field. The read transducer also includes a pinned layer having a fixed magnetization and a direction of the fixed magnetization forms a right angle with the magnetization bias of the free layer. The read transducer targets a readback location on a track boundary between adjacent tracks and generates a read signal indicative of perpendicular and cross-track fields of the adjacent tracks.

A recording head has a near-field transducer proximate a media-facing surface of the recording head. The near-field transducer extends a first distance away from the media-facing surface. A waveguide overlaps and delivers light to the near-field transducer. Two subwavelength focusing mirrors are at an end of the waveguide proximate the media-facing surface. The subwavelength mirrors are on opposite crosstrack sides of the near-field transducer and separated from each other by a crosstrack gap. The subwavelength focusing mirrors each include a first material at the media-facing surface and a liner that covers an edge of the mirror.

A data storage device is disclosed comprising a head actuated over a magnetic media, wherein the head comprises a laser and a near field transducer (NFT). A thermal gradient produced in the magnetic media by the NFT is periodically measured, and a failure of the NFT is predicted based on a slope of the thermal gradient measurements.

A heat-assisted magnetic recording head includes a near-field transducer (NFT). The NFT includes a near-field emitter configured to heat a surface of a magnetic disk, and a heat sink. The heat sink includes at least one of rhodium, copper, tungsten, tantalum, iridium, platinum, ruthenium, nickel, or iron.

Described are magnetic recording heads that include a read transducer and a write transducer, with the two transducers being arranged in a side-by-side configuration.

A data storage device is disclosed comprising a first head actuated over a first disk surface, the first head comprising a plurality of elements including a first element. During a first write operation of the first head, a first bias signal having a first polarity is applied to the first element, and a write interval of the first write operation is measured. During a non-write mode of the first head, a second bias signal having a second polarity opposite the first polarity is applied to the first element during a reverse bias interval that is based on the write interval of the first write operation.

A method of operating a HDD having a read/write head configured for Perpendicular Magnetic Recording (PMR) and configured for use in Thermally Assisted Magnetic Recording (TAMR). By using selected settings of a power ratio (PR) value to ensure that accurate fly height (FH) measurements of head-disk interference (HDI) can be taken during write touchdowns (TDs), head damage can be eliminated during HDI events. Under normal operating conditions the PMR head develops a sharp protrusion due to heating from the TAMR apparatus as well as the write current and read and write heaters. The sharp protrusion is prone to striking the disk surface, instead of the shields doing so. The shields would be more capable of absorbing the HDI, which would allow the HDI sensors (HDIs) to provide a more sensitive reading of the HDI which would prevent head wear caused by the sharp protrusion. By adjusting the power ratio (PR) to be at least the turning point (TP) value, the write shield will approach the disk surface before the sharp protrusion.

This magnetic head, which reads and writes magnetic information, prevents a signal from being read between the magnetic head and the write circuit during reading of magnetic information. A card reader 1 is provided with a magnetic head 6 which reads and writes magnetic information. Bidirectional diodes 54A, 54B are arranged inside of a head case 21 of the magnetic head 6. A write signal from a write circuit 72 is inputted via the bidirectional diodes 54A, 54B to a writing coil 34 wound around a core 32 of the magnetic head 6. The bidirectional diodes 54A, 54B and a demodulation IC 61 are mounted on a first board surface 62A of a control circuit board 62, and the control circuit board 62 is fixed to the head case 21 so that the bidirectional diodes 54A, 54B and the demodulation IC 61 are covered by the head case 21.

A HAMR data storage device may include a magnetic media and a slider comprising: a main pole, a waveguide, and a near-field transducer (NFT) situated between the main pole and the waveguide, wherein an air-bearing surface (ABS) of the slider comprises a transparent overcoat layer situated over the main pole, the waveguide, and the NFT, and wherein the transparent overcoat layer has a particular thickness such that, during an operational phase of the HAMR data storage device, a gap between a media-facing surface of the transparent overcoat layer and the magnetic media is less than about 0.5 nm.