A method of operating an HDD having a slider-mounted read/write head that is configured for dynamic fly-height operation (DFH) and includes at least one head-disk interference sensor (HDIs). By operating the DFH to lower the head and subjecting the HDIs signal to a power-law enhancement, a consistent and accurate determination of the touchdown power (TDP) can be obtained. Combining absolute TDP determination with a method for measuring relative changes of FH, an absolute determination of FH can be determined.

A data storage device is disclosed comprising a head actuated over a disk surface, wherein the head comprises a plurality of elements including a write assist element. A bias signal applied to the write assist element is controlled such that the write assist element is substantially unprotruded, and while the write element is substantially unprotruded, an air bearing resonant frequency (ABRF) of the head and disk surface is measured. The bias signal applied to the write assist element is controlled such that the write assist element protrudes toward the disk surface, and while the write assist element protrudes toward the disk surface, the head is excited at the measured ABRF and the head touching down onto the disk surface is detected.

A disk drive head assembly includes a spin torque oscillator (STO) situated between a main pole and a trailing shield. A head-disk interference (HDI) sensor is placed between the main pole and a read sensor shield. A trace is connected between a preamplifier and the head assembly for providing a first biasing voltage level to the spin torque oscillator (STO) and to the head-disk interference (HDI) sensor for determining resistance changes in the head-disk interference (HDI) sensor. Further, the preamplifier is configured for determining a resistance change in the head-disk interference (HDI) sensor based on a change in current through the head-disk interference (HDI) sensor. The spin torque oscillator (STO) and the head-disk interference (HDI) sensor are connected in parallel to two connectors from the two contacting pads on the preamplifier.

A disk drive head assembly includes a spin torque oscillator (STO) situated between a main pole and a trailing shield. A head-disk interference (HDI) sensor is placed between the main pole and a read sensor shield. A trace is connected between a preamplifier and the head assembly for providing a first biasing voltage level to the spin torque oscillator (STO) and to the head-disk interference (HDI) sensor for determining resistance changes in the head-disk interference (HDI) sensor. Further, the preamplifier is configured for determining a resistance change in the head-disk interference (HDI) sensor based on a change in current through the head-disk interference (HDI) sensor. The spin torque oscillator (STO) and the head-disk interference (HDI) sensor are connected in parallel to two connectors from the two contacting pads on the preamplifier.

A recording head comprises a waveguide extending to an air-bearing surface, and the waveguide comprises a core surrounded by cladding layers. A near-field transducer is disposed on a first side of the core, and a reflector, comprising a layer of metallic material, is disposed on a second side of the core facing away from the first side. The reflector extends beyond the core in a cross-track direction and extends in a direction normal to the air-bearing surface. The reflector has a thickness in a downtrack direction of less than 200 nm.

A method includes producing a first surface acoustic wave (SAW) on a magnetic head slider using a first interdigitated transducer (IDT), wherein the SAW has a first set of wave characteristics. The method also includes receiving the first SAW at a second IDT on the magnetic head slider. The method also includes analyzing the SAW for a second set of wave characteristics. The method also includes determining, based on the analyzing, that a substance having at least one characteristic is located in a path of the SAW on the magnetic head slider.

Methods and systems are disclosed for controlling fly-height of a read/write (RW) head. In an embodiment, a RW channel detects a servo gate signal and toggles a mode signal within a preamplifier from a RW data mode signal to a fly-height control (FHC) mode signal. In response to the FHC mode signal, the RW channel transmits FHC data over a differential interface to the preamplifier.

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.

A slider configured for heat-assisted magnetic recording comprises a magnetic writer, a near-field transducer, and an optical waveguide coupling the near-field transducer to a light source. The writer is situated proximate the near-field transducer at an air bearing surface of the slider and comprises a first return pole, a second return pole, and a write pole situated between and spaced apart from the first return pole and the second return pole. A structural element is situated at or near the air bearing surface between the write pole and one of the first and second return poles. The structural element comprises a cavity. A thermal sensor is disposed in the cavity. The thermal sensor is configured for sensing contact between the slider and a magnetic recording medium, asperities of the medium, and output optical power of the light source.

A hard disk drive has a gas-bearing slider supporting a write head with an electrically conductive structure, like a spin-torque oscillator (STO), in the write gap, and dual independent interface voltage control (IVC) circuitry coupled to elements on the slider. A first IVC circuitry provides a bias voltage to the slider body to assure substantially zero electrical potential between the slider body and the disk to minimize slider-disk contact and lubrication pick-up. A second IVC circuitry operates independently of the first IVC circuitry and provides a bias voltage to the electrically conductive structure region to assure a negative potential of the electrically conductive structure region relative to the disk to minimize degradation of the slider overcoat and thus oxidation of the electrically conductive structure.