Numerical analysis of microwaviness-excited slider vibration in proximity and contact regimes

Ono, Kyosuke

doi:10.1299/transjsme.16-00208

Cited by 3 publications

(2 citation statements)

References 35 publications

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“…Vakis et al discussed the dynamic HDI instability with friction for light contact recording using the two-degree-of-freedom dynamic contact simulation [11]. Ono numerically analyzed the microwaviness-excited slider vibration in proximity and asperity contact regimes [12], and the surface forces between the diamond-like carbon (DLC) surface covered with a monolayer lubricant film and magnetic head slider [13]. In their study, the contact force on the head slider between the head and disk with a molecularly thin lubricant film was derived from the contact theories on the surface roughness asperities and microwaviness.…”

Section: Introductionmentioning

confidence: 99%

Effective Elastic Moduli of Magnetic Disks with Molecularly Thin Liquid Lubricant Films Determined Using Ar-Gas Cluster Ion Beam

et al. 2022

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To improve the reliability of the design of hard disk drives, this study aims to determine the effective elastic properties of disks with perfluoropolyether lubricant films on the diamond-like carbon overcoats of magnetic disks. However, the determination of the effective elastic modulus of multi-layered film from molecularly thin lubricant films (1.0 nm) and diamond-like carbon overcoats is extremely difficult because these layers are ultra-thin. Therefore, the method of etching in the depth direction with an Ar-gas cluster ion beam is proposed in this study. The lubricants D-4OH and Z-tetraol, comprising different main chains, are applied to the samples at varying thicknesses. Additionally, the D-4OH is UV-treated to vary the bonded film thickness. The effective Young's modulus of disk with D-4OH is approximately 60 and 20 GPa at 1.2 and 2.9 nm film thicknesses, respectively, whereas that of Z-tetraol is approximately 16 GPa at 1.2 nm film thickness, and exhibits less dependence on the film thickness than that of D-4OH. The effective Young's modulus of D-4OH increases with increasing bonded thickness. These results suggest a significant variation in the effective Young's modulus of disks with the lubricant film based on the film thickness, molecular structure, and adsorption state.

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Section: Introductionmentioning

confidence: 99%

Effective Elastic Moduli of Magnetic Disks with Molecularly Thin Liquid Lubricant Films Determined Using Ar-Gas Cluster Ion Beam

et al. 2022

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“…Ultrathin films with nanometer order thickness are used for commercial products such as the diamond-like carbon (DLC) overcoat of magnetic disks and heads in hard disk drives (HDDs). Ono (2016Ono ( , 2017 performed a numerical analysis of microwaviness-excited slider vibration in proximity and contact regimes and surface force of DLC surface covered with monolayer lubricant film on magnetic disks. Vakis et al (2009) discussed the dynamic head-disk interface instabilities with friction for light contact (surfing) recording on HDDs.…”

Section: Introductionmentioning

confidence: 99%

Elastic modulus measurement of ultrathin layer using gas cluster ion beam

Tani

Lü

Koganezawa

et al. 2021

JAMDSM

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Numerical analysis of microwaviness-excited vibrations of head slider at touchdown

Ono¹

2017

Transactions of the JSME (In Japanese)

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Numerical analysis of microwaviness-excited vibrations of head slider at touchdownVibration characteristics of a flying head slider in hard disk drives at touchdown attract strong interest because head-disk spacing must be decreased to less than 1 nm in order to increase recording density. This study first evaluates head-disk interfacial force based on rough surface adhesion contact models and a simple air-bearing force model. Then, microwavinessexcited vibration of single-degree-of-freedom slider model at touchdown was numerically simulated in more detail than the previous study. It was found that the slider exhibits a MW-excited vibration having low frequency components of less than 100 kHz at touchdown and shifts to severe contact state near the boundary of static instability onset. When a small static unstable region is generated by decreasing air-bearing stiffness ratio, the occurrence of the low frequency spacing variation is interrupted by temporal flying state (loss of contact). When the static unstable region further increases by decreasing air-bearing stiffness ratio, the spacing variation with low frequencies can appear only at the beginning of contact and immediately jumps to a light contact state and then shifts to a perfect flying state during a long input power range and eventually jumps to a heavy contact state. These calculated results seem to correspond to the actual slider dynamic behaviors at touchdown in the inner, outer and middle diameter regions. The possibility of surfing recording is discussed from the analytical and experimental evidences.

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Numerical analysis of microwaviness-excited slider vibration in proximity and contact regimes

Cited by 3 publications

References 35 publications

Effective Elastic Moduli of Magnetic Disks with Molecularly Thin Liquid Lubricant Films Determined Using Ar-Gas Cluster Ion Beam

Effective Elastic Moduli of Magnetic Disks with Molecularly Thin Liquid Lubricant Films Determined Using Ar-Gas Cluster Ion Beam

Elastic modulus measurement of ultrathin layer using gas cluster ion beam

Numerical analysis of microwaviness-excited vibrations of head slider at touchdown

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