Sae Magnetics (h.k.) Limited

Hitachi Global Storage Technologies Netherlands B.v.

Headway Technologies, Incorporated

Western Digital Technologies, Inc.

Intematix Corporation

Other

Hgst Netherlands, B.v.

Hitachi Global Storage Technologies

Hitachi Global Storage Technologies B.v.

Sae Magnetics (hk) Lid.

Qinghua Zeng

Ellis T Cha

Yen Fu

Chao-Hui Yang

Fu-Ying Huang

Siu Yin Ngan

Toshiki Hirano

David W Albrecht

Soramany Ka

Kowang Liu

Akihiko Aoyagi

Yi-Qun Li

Tzong-Shii Pan

Bernhard E Knigge

Li-Yan Zhu

Gang Wang

Ullal Vasant Nayak

Francis C Lee

Noureddine Kermiche

William Bernard Boyle

Guoxiao Guo

Yuhui Tang

Xuhui Jin

Sukumar Rajauria

Remmelt Pit

Weidong Huang

Kei Yasuna

Robert Nolan Payne

Vedantham Raman

Masaru Furukawa

Tomokazu Ishii

Kazuhiro Saito

Guoqiang Zheng

Dan Wang

Jimmy Zhang

Zhijun Liu

Various illustrative aspects are directed to a data storage device including one or more disks, an actuator mechanism configured to position a selected head among one or more heads proximate to a corresponding disk surface among the one or more disks, the selected head comprising a write element and an assistive energy emitter, and one or more processing devices configured to, individually or in combination: apply an assistive energy current to the assistive energy emitter while refraining from applying a write current to the write element, and vary a level of the assistive energy current over time while refraining from applying the write current to the write element.

Energy-assisted magnetic recording data storage device with opportunistic boosted laser pre-biasing

A data storage device comprises a disk and a head having a read and write elements. A read heater is powered based on a dual heater ratio (DHR) to thermally adjust a spacing of the read element from a disk surface, and a write heater is powered based on the DHR to thermally adjust a spacing of the write element from the disk surface. A read spacing slope profile is determined comprising read touchdowns (TDs) over a range of DHRs, and a write spacing slope profile is determined comprising write TDs over the range of DHRs. An operating DHR of the head is set to be where the read spacing slope profile intersects the write spacing slope profile.

Pole tip recession compensation by dual heater ratio optimization in a hard disk drive

Methods, data storage devices, and computer-readable media for setting the flying height of a recording head are disclosed. A method may set a value of a control parameter of the recording head to force a predetermined location of the recording head to be a touchdown location. The method may involve incrementally moving the recording head toward a surface of a recording media, and, using a temperature sensor of the recording head, detecting an onset of touchdown at the touchdown location as the recording head is incrementally moving toward the surface of the recording media. The method may set the fly-height control power by backing off from an initial fly-height control power value, which may be a sum of a power level at which the onset of touchdown at the touchdown location was detected and a power corresponding to the value of the control parameter.

Touchdown detection and write-spacing setting in magnetic recording heads with protruding features

Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head having read and write portions configured to read data from and write data to the disk; read and write heaters configured to thermally adjust read and write spacings of the read and write portions from the disk surface; and a controller configured to control power applied to the read and write heaters based on a dual heater power ratio (DHR) of the respective power applied to each heater. The DHR is set based on a point during touchdown at which a reader shield and a writer shield have maximum contact with the surface of the disk (DHRmax).

Adaptive dual heater mode for hard disk drive

A PMR, TAMR or MAMR (Perpendicular Magnetic Recording, Thermally Assisted Magnetic Recording or Microwave Assisted Magnetic Recording) slider-mounted read/write head produces less heat during operation by using magnetic read shields in which are embedded a patterned layer of thermally absorbing material. At least one shield includes a heating coil which is used to adjust the fly-height of the slider by creating a thermal protrusion at the slider ABS. When additional sources of energy, such as laser heating, microwave heating or the write coil itself, are applied to the recording medium, the shields can overheat, adversely affecting their performance. The patterned layer of heat absorbing material reduces the flow of heat from the thermal heating coil to the air bearing surface (ABS) thus cooling the region around the write head while not adversely affecting the shape of the thermal protrusion.

Patterned reader shields for a cooler reader

A Perpendicular Magnetic Recording (PMR) head is configured for use in Thermally Assisted Magnetic Recording (TAMR). Two or three contiguous write shields, of various widths and thicknesses, formed on a leading edge side of the write gap (WG), main pole (MP) and near-field transducer (NFT), protect the head during write touchdowns (TD) and signal the approach of such a touchdown. Moreover during a write touchdown the contact with the head is restricted to the large write shields, producing a large touchdown area (TDA) and insuring the lifetime of the head.

Protective shields under touchdown conditions for thermally assisted perpendicular magnetic recording

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.

TD detection with enhanced HDIs signal

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.

High power ratio mode for TAMR drives

A PMR read/write head configured for thermally assisted recording (TAMR) includes thermally active bumper pads formed to each side of a write element to provide enhanced touchdown (TD) protection to the write head element where it emerges adjacent to the plasmon near-field spot produced by the TAMR apparatus. The bumper pads are disposed about the write head and absorb heat energy generated by active heating elements, the write current and the energy generated by the TAMR apparatus. Absorption of this energy causes the bumper pads to expand and protrude outward from the slider ABS to protect the read/write head from both intentional and unanticipated touchdown events. The PMR read/write head is then mounted on a slider and the assembly is incorporated into a hard disk drive (HDD).

Bumper pad design for TAMR drives

A slider design for a hard disk drive (HDD) features an air-bearing surface (ABS) topography with soft bumper pads (SBP) formed proximally to corners of the leading edge and the trailing edge. The bumper pads are formed by a process that combines the use of a first photomask for subtractive etching of the ABS to form pedestals, followed by additive depositions onto the pedestals using a second lift-off photomask. The additive process deposits sequences of Si layers and diamond-like carbon (DLC) layers to produce a soft bumper pad that is energy absorbing and heat conducting, thereby protecting the recording media from surface damage and thermal erasures.

ABS design with soft bumper pads (SBP) for mitigating media damage and thermal erasure in hard disk drives (HDD)

Dynamic fly height (DFH) controlled read/write heads using multiple heaters have their heater powers set within a range of ratios that allows minimum clearances to be set between the read-gap and the write-gap and the surface of a disk, thereby providing improved touch-down detection. Determining the correct range of power ratios requires varying the ratio to create an adjustable protrusion profile for the read and write elements in the head and measuring values of the ratio and corresponding values of read gap and write gap clearances that create points of minimum clearance. By adjusting the ratio of power supplied to the heaters, different protrusion profiles can be produced, clearance control for sigma reduction can be obtained and read/write readiness and operation consistency and reliability can be improved.

Head DFH protrusion shape calibration by HDI sensor

A photoluminescent material has the characteristic of a long photoluminescence decay and has the general composition CaAScMSiEO:mCe,nMn, where A is at least one divalent cation including Sr, Ba or a combination of monovalent and trivalent cations including combinations of Li, Na, K, B, Al and Ga; M is at least one trivalent cation including Al, Ga, or a divalent cation including Mg, E is a combination of a trivalent and a pentavalent cation including B, Al, Ga, N and P, or a combination of monovalent and trivalent cations including Li, Na, K, B, Al, Ga, N and P. The A cation replaces Ca; the M cation replaces Sc, and E replaces Si. This Mn and Ce doped phosphor emits in the yellow to green with a peak at around 510 and/or 560 and 690 nm. The phosphor material has applications in LED illumination systems.

Long decay phosphors for lighting applications

Chlorosilicate-based phosphors configured to emit yellow-green light in a wavelength ranging from about 500 nm to about 560 nm in response to an excitation source emitting at about 400 nm to about 480 nm, wherein the light emitted by the phosphor has a decay time ranging from about 1 millisecond (1 ms) to about 10 milliseconds (10 ms). The phosphor comprises a compound of the family CaAEuMgBMn(SiCO)R, where A is at least one divalent cation including Ca, Sr, Ba; B is Zn or Cd, or a divalent metal ion other than an alkaline earth; C is a cation, including at least one of Ge, Al, B, Gd, Ga, and N, and R is an anion, including F, Cl, Br, I, all respectively either individually, or in combinations.

Millisecond decay phosphors for AC LED lighting applications

Methods are provided for determining the heater power level of a dynamic flying height (DFH) type write head at which a touch down (TD) occurs. Each method makes use of the DC component of a head-disk interference (HDI) sensor and the determination of the TD heater energy is deduced from certain characteristics of the function relating heater power to HDI DC signal strength. Characteristics that provide reliable indication of a TD include points of minimum slope, structure of the slope's slope and the properties of a linear fit to the slope if the slope does not converge to a consistent value. It is found that the use of all methods in combination allow a reliable TD determination under virtually all conditions.

Touch down detection with HDI sensor DC mode

A method to compensate for spacing variations between a dynamic fly height (DFH) controlled read/write head and a rotating disk surface. Using a HDI sensor or equivalent indicator of touchdowns, a power profile is calculated for an arbitrary track on a disk. The profile tracks disk topography by recording touchdown power at each of a series of sectors into which the track is subdivided. The resulting power profile, smoothed and expressed as a function of sector position, substitutes for the usual constant TD power setting that provides only an uncompensated range of spacing variations. A fixed back-off spacing power is added to the power profile enabling the head to fly over the track at a constant spacing. The power profile can be calculated to account for various temperature and pressure conditions.

Spacing fluctuation compensation

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Fremont, CA, United States of America

Qinghua Zeng