A damage quantification method for air-bearing-surface overcoats on magnetic head sliders

ABSTRACTLaser-induced etching of polycrystalline Al2O3TiC material by a tightly-focused CW Ar ion laser has been investigated in a KOH solution with different concentrations. It is found that the KOH concentration can strongly affect the etching quality where low KOH concentration can result in rough and irregular patterns. The etching effect is also related to laser power and scanning speed. Laser-induced etching of polycrystalline AI2O3TiC in a KOH solution is found to be a photothermal reaction in which a threshold laser power exists. With an appropriate set of etching parameters, well defined grooves can be obtained with clean side walls and with an etching rate up to several hundred micrometers per second. It is also found that the grains in the polycrystalline Al2O3TiC material play an important role in the etching dynamics and etching quality. This etching process is believed to be applicable to the formation of a slider surface of magnetic heads in the future.

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Magnetic head field over the air bearing surface as visualised by the projection of patterned electron beam

INTERMAG 2000 Digest of Technical Papers. 2000 IEEE International Magnetics Conference ◽

10.1109/intmag.2000.871828 ◽

2005 ◽

Author(s):

H. Suzuki ◽

K. Itoh ◽

K. Nakamura

Keyword(s):

Electron Beam ◽

Air Bearing ◽

Magnetic Head ◽

Bearing Surface

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Magnetic head field over the air-bearing surface as visualized by the projection of a patterned electron beam

IEEE Transactions on Magnetics ◽

10.1109/20.908918 ◽

2000 ◽

Vol 36 (5) ◽

pp. 3614-3617 ◽

Cited By ~ 4

Author(s):

H. Suzuki ◽

T. Shimakura ◽

K. Itoh ◽

K. Nakamura

Keyword(s):

Electron Beam ◽

Air Bearing ◽

Magnetic Head ◽

Bearing Surface

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S1140301 Reduction of contact vibration by nano-textures on air bearing surface of magnetic head slider

The Proceedings of Mechanical Engineering Congress Japan ◽

10.1299/jsmemecj.2014._s1140301- ◽

2014 ◽

Vol 2014 (0) ◽

pp. _S1140301--_S1140301-

Author(s):

Masato YASUI ◽

Hiroshi TANI ◽

Shinji KOGANESAWA ◽

Norio TAGAWA

Keyword(s):

Air Bearing ◽

Magnetic Head ◽

Bearing Surface ◽

Head Slider

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Thermal Analysis for the Protrusion of Magnetic Head

Magnetic Storage Symposium: Frontiers of Magnetic Hard Disk Drive Tribology and Technology ◽

10.1115/2003-trib-334 ◽

2003 ◽

Author(s):

Junguo Xu ◽

Masayuki Kurita ◽

Shozo Saegusa

Keyword(s):

High Frequency ◽

Maximum Temperature ◽

Air Bearing ◽

Magnetic Head ◽

Bearing Surface ◽

Applied Current ◽

High Resolution Measurement ◽

Resolution Measurement ◽

Thermal Protrusion ◽

Head Coil

The thermal protrusion of a magnetic head was investigated through, first a high-resolution measurement of temperature distribution over the air bearing surface (ABS) and head coil and, second, a numerical calculation of the head protrusion. It was found that the temperature on the ABS results in a “butterfly”-shaped distribution. It was also found that an eddy current induced by high frequency write-current significantly increases the temperature of read/write elements. Moreover, the point of maximum temperature changed from the head core to the write gap when the applied current was switched from DC to AC. It was also found that a write-current induced head protrusion caused more deformation of the alumina over coat in the horizontal direction and that an ambient-temperature-induced head protrusion caused more deformation around the read-write elements. Furthermore, it is clarified that film materials with higher elastic modulus, lower expansion rate, and higher thermal conductivity reduce the head thermal protrusion. Finally, to reduce write-current-induced head protrusion, a novel thermally improved head structure is proposed.

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Laser Dry Cleaning of Zro2 Particles from Air Bearing Surface of Magnetic Head Sliders

MRS Proceedings ◽

10.1557/proc-397-329 ◽

1995 ◽

Vol 397 ◽

Cited By ~ 1

Author(s):

Y.F. Lu ◽

W.D. Song ◽

M.H. Hong ◽

T.C. Chong ◽

T.S. Low

Keyword(s):

Laser Fluence ◽

Repetition Rate ◽

Pulse Number ◽

Air Bearing ◽

Magnetic Head ◽

Bearing Surface ◽

Cleaning Efficiency ◽

Dry Cleaning ◽

Average Acceleration ◽

Number Of Particles

ABSTRACTLaser dry cleaning of ZrO2 particles from air bearing surface (ABS) of magnetic head sliders has been investigated. The experimental results show that the cleaning threshold of removing ZrO2 particles from ABS is about 100 mJ/cm2. For laser fluence larger than this threshold, cleaning efficiency increases with increasing laser fluence and pulse number, but does not depend on repetition rate up to 30 Hz. The mechanisms of this laser dry cleaning are laser-induced ABS vibration, particle thermal expansion and particle vibration, which produce forces strong enough to detach ZrO2 particles from ABS. With increasing laser fluence and pulse number, the average acceleration and vibration number of particles induced by laser increase respectively, so that it is easier to remove particles which corresponds to higher cleaning efficiency. For fixed laser fluence and pulse number, changing the repetition rate does not change the average acceleration or the vibration number of particles, therefore laser cleaning efficiency is almost the same for different repetition rates.

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Parameter Effects on Thermal Protrusions of Magnetic Head Sliders

World Tribology Congress III, Volume 1 ◽

10.1115/wtc2005-63784 ◽

2005 ◽

Author(s):

M. Kurita ◽

J. Xu

Keyword(s):

Heat Transfer ◽

Hard Disk Drives ◽

Flying Height ◽

Parameter Study ◽

Air Bearing ◽

Disk Drives ◽

Magnetic Head ◽

Bearing Surface ◽

Simulated Temperature ◽

Height Change

The heat transfer in the magnetic head sliders in hard disk drives, the thermal protrusion (TPR) of the head elements, and the flying height change of such sliders were numerically simulated. A simulated temperature distribution of the air-bearing surface correlated well with our experimental results. A parameter study showed that decreasing the thickness of the alumina base coat or increasing the size of the pole and shields of the head elements can reduce the magnitude of write-current-induced protrusion (W-TPR). However, a longer pole and shields increase ambient-temperature-induced protrusion (T-TPR). For W-TPR, the reduced flying height of the slider is partly compensated for by increased air pressure on the air-bearing surface. However, almost the entire magnitude of T-PTR translates into a reduction in flying height.

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An Efficient Damage Quantification Method for Cylindrical Structures Enhanced by a Dry-Point-Contact Torsional-Wave Transducer

Applied Sciences ◽

10.3390/app12020572 ◽

2022 ◽

Vol 12 (2) ◽

pp. 572

Author(s):

Shengbo Shan ◽

Yongdong Pan ◽

Shengyu Xiao

Keyword(s):

Point Contact ◽

Low Frequency ◽

Wave Interaction ◽

Torsional Wave ◽

Wave Reflections ◽

Cylindrical Structures ◽

Quantification Method ◽

Damage Quantification ◽

Torsional Waves ◽

Theoretical Analyses

Quantification of damage sizes in cylindrical structures such as pipes and rods is of paramount importance in various industries. This work proposes an efficient damage quantification method by using a dry-point-contact (DPC) transducer based on the non-dispersive torsional waves in the low-frequency range. Theoretical analyses are first carried out to investigate the torsional wave interaction with different sizes of defects in cylindrical structures. A damage quantification algorithm is designed based on the wave reflections from the defect and end. Capitalizing on multiple excitations at different frequencies, the proposed algorithm constructs a damage image that identifies the geometric parameters of the defects. Numerical simulations are conducted to validate the characteristics of the theoretically-predicted wave-damage interaction analyses as well as the feasibility of the designed damage quantification method. Using the DPC transducer, experiments are efficiently carried out with a simple physical system. The captured responses are first assessed to confirm the capability of the DPC transducer for generating and sensing torsional waves. The sizes of the defects in two representative steel rods are then quantified with the proposed method. Both numerical and experimental results demonstrate the efficacy of the proposed damage quantification method. The understandings of the wave-damage interaction and the concept of the damage quantification algorithm lay out the foundation for engineering applications.

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