Hgst Netherlands, B.v.

Hitachi, Ltd.

Western Digital Technologies, Inc.

Masaru Furukawa

Junguo Xu

Jianhua Li

Masato Shiimoto

Guoxiao Guo

Shaomin Xiong

Toshiya Shiramatsu

Kei Yasuna

Yukio Kato

Duc H Banh

Makoto Satou

Kenichiro Takahashi

Yohji Maruyama

Masukazu Igarashi

Sukumar Rajauria

Qinghua Zeng

Takayoshi Ohtsu

Kenji Suzuki

Yuki Shimizu

Masato Matsubara

Kenichi Kuramoto

Yuichi Aoki

Kenji Tasaka

Jimmy Zhang

Yuichiro Sano

Aiko Sakoguchi

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 one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of a corresponding disk of the one or more disks; and one or more processing devices. The one or more processing devices are configured to: determine a plurality of readings of an energy sensor output from an energy sensor disposed on the selected head during a rotation of the corresponding disk; determine an average of the readings of the energy sensor output; and use the average of the readings of the energy sensor output as a control parameter for controlling a fly height of the selected head.

Energy-assisted magnetic recording data storage device with averaged measurement mitigation of energy component protrusion

Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuator assembly comprising a head, and configured to position the head over a corresponding disk surfaces; and one or more processing devices, wherein the head comprises: a write element; a laser unit; and a fly height control element, and wherein the one or more processing devices are configured to: iteratively perform write start operations of write start patterns with the head on the corresponding disk surface, at a plurality of values of at least one of laser pre-bias current, and write backoff; detect pattern signal amplitudes of the write start patterns on the corresponding disk surface; and determine a relation of write backoff to laser pre-bias current for the head, based at least in part on the pattern signal amplitudes.

Determining laser induced thermal protrusion and laser threshold in heat-assisted magnetic recording (HAMR) data storage

Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuator assembly comprising a head, and configured to position the head over a corresponding disk surface; and one or more processing devices, the head comprising: a write element; a laser unit; and a fly height control element, and wherein the one or more processing devices are configured to: iteratively perform spiral write operations of spiral patterns comprising a plurality of sync marks with the head on the corresponding disk surface, wherein the spiral write operations are performed at: a plurality of values of laser pre-bias current, write backoff, and/or start disk phase; detect pattern signal amplitudes of the spiral patterns on the corresponding disk surface; and determine a relation of write backoff to laser pre-bias current for the head, based on the pattern signal amplitudes of the spiral patterns.

Method to measure thermal protrusion by sensing spacing change due to pre-lasing

Embodiments of the present invention generally relate to a MAMR head. The MAMR head includes an STO and an embedded contact sensor (ECS). The STO and the ECS are electrically connected in series and are connected to the same terminals. During operation, the current applied to the STO is controlled with respect to a change in resistance of the ECS.

Magnetic head for microwave assisted magnetic recording

Embodiments of the present invention generally relate to a microwave assisted magnetic recording (MAMR) head. The MAMR head includes a main pole, a trailing shield, and a spin torque oscillator (STO) disposed between the main pole and the trailing shield. The STO is recessed from an air bearing surface.

MAMR head with recessed STO

Embodiments disclosed herein generally relate to the data storage field and hard disk drives (HDD) using microwave assisted magnetic recording (MAMR) technology. Aspects of the preferred embodiments are to prevent the breakdown of spin torque oscillators (STO) due to large amounts of current flowing through the STO during head/disk contact. A magnetic head slider is disposed above and spaced apart from a disk. A STO is formed on a section of the magnetic head slider. Two electrodes are coupled to the STO, and one electrode has a higher potential than the other electrode. A preamplifier is adapted to send a current through the two electrodes, resulting in the higher potential electrode protruding closer to the disk than the lower potential electrode. Current then flows from one electrode to the disk without flowing through the STO, and breakdown of the STO is prevented.

Head structure with electric damage protection for a microwave-assisted hard disk drive

A method, apparatus, and system are provided for implementing enhanced surface analysis test (SAT) function for microwave assisted magnetic recording (MAMR) hard disk drives (HDDs) using embedded contact sensor (ECS) and spin-torque oscillator (STO) signals. A preamplifier circuit receives the embedded contact sensor (ECS) and spin-torque oscillator (STO) signals and compares the received ECS and STO signals to identify magnetic disk media defects including bumps or thermal-asperity (TA) defects and pits or hole defects.

Implementing surface analysis test (SAT) function for microwave-assisted magnetic recording (MAMR) HDD with embedded contact sensor (ECS) and spin torque oscillator (STO) signals

An embedded contact sensor (ECS) element for fly-height control and touchdown detection. An embedded contact sensor (ECS) element with a resistance that changes with a temperature change, which senses a clearance change between a head slider and a disk of a disk drive. A resistance measurement section, within said head IC, that determines a value of direct current resistance (DCR) of said ECS element, wherein said value of DCR changes with a temperature change, wherein said temperature change is caused by an air bearing cooling and frictional induced heating at a head disk interface. A resistance slope to fly-height conversion section that dynamically determines a target fly-height value for said head slider over said disk based on changes in said value of DCR.

Fly-height control and touchdown detection

A method, apparatus, and system are provided for preventing electrostatic discharge (ESD) in hard disk drives using spin-torque oscillator (STO) for microwave assisted magnetic recording (MAMR). A control circuit adjusts a disk electrical potential with an electrical potential of a spin-torque oscillator (STO) element. The control circuit maintains a potential difference of less than about 115 millivolts (mV) between the disk and the STO element.

Implementing enhanced ESD prevention for hard disk drives using spin-torque oscillator (STO)

A microwave-assisted magnetic recording head includes: a main magnetic pole that generates a recording magnetic field to be recorded on a magnetic recording medium; a shield; and an oscillator that is provided between the main magnetic pole and the shield and generates a microwave magnetic field. The microwave-assisted magnetic recording head is provided with a thermal expansion device for adjusting a relative position between the oscillator and the main magnetic pole so as to be able to independently adjust a recording magnetic field from the main magnetic pole and a microwave magnetic field from the oscillator.

Microwave-assisted magnetic recording head and magnetic read/write apparatus using the same

A magnetic head slider inspection device including a motor unit for revolving a disk medium, a slider unit provided with a reproducing head, which is levitated from a surface of the disk medium under force generated by the revolving disk medium, a magnetic field generator positioned at an opposite side of the disk medium with respect to the slider unit for generating a magnetic field substantially perpendicular to the disk medium surface, and a circuit unit for generating the magnetic field from the magnetic field generator, and measuring a resistance value of the reproducing head levitated from the disk medium surface.

Magnetic head slider inspection device

A slider comprising a contact sensor element configured to respond to a change in resistance due to a change in temperature, and a shield structure. The shield structure comprises a lower thermal conductivity than the contact sensor element and a greater hardness than the contact sensor element.

Noise and particle shield for contact sensor in a slider

Provided is a head slider that can heat a recording medium with a simple structure. In the head slider (), a hole portion () having an opening in a medium facing surface () facing a disk-shaped recording medium () is formed, and a heating element () that is heated by being energized and a reflection portion () for reflecting heat radiated from the heating element () toward the disk-shaped recording medium () are disposed in the hole portion ().

Head slider, head assembly, and magnetic disk device

An information recording apparatus includes a medium for recording information; a head slider including a device for writing the information onto the medium and a reflective surface for reflecting light; a light emitting portion for generating emission light toward the reflective surface; a light receiving portion for detecting light reflected on the reflective surface; and a regulating mechanism for adjusting an amount of the emission light from the light emitting portion in a mode of information recording onto the medium in correspondence to a result of the detection.

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Fujisawa, Japan

Masaru Furukawa