Flying-height reduction of magnetic-head slider due to thermal protrusion

Kurita, Masayuki; Xu, Junguo; Tokuyama, M.; Nakamoto, K.; Saegusa, Shozo; Maruyama, Y.

doi:10.1109/tmag.2005.855240

Cited by 74 publications

(6 citation statements)

References 5 publications

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“…With the rapid progress in fabricating and manufacturing of micro/nanoscale devices, understanding the fluid and heat transfer characteristics under nanoscale confinement becomes essential to improve the performance of the microfluidic device components and micro/nano electromechanical systems. Further examples which also deal with transport phenomena on these scales include the heat and mass transfer through carbon nanotubes [1,2] or the heat transfer between the head and disk in magnetic disk drives [3][4][5]. In such devices, gas experiences levels of rarefaction ranging from continuum behavior to the free molecular regime.…”

Section: Introductionmentioning

confidence: 99%

Interplay of confinement and density on the heat transfer characteristics of nanoscale-confined gas

Rabani

Heidarinejad

Harting

et al. 2018

International Journal of Heat and Mass Transfer

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The effect of changing the Knudsen number on the thermal properties of static argon gas within nanoscale confinement is investigated by three-dimensional molecular dynamics simulations. Utilizing thermalized channel walls, it is observed that regardless of the channel height and the gas density, the wall force field affects the density and temperature distributions within approximately 1 nm from each channel wall. As the gas density is increased for constant channel height, the relative effect of the wall force field on the motion of argon gas atoms and, consequently, the maximum normalized gas density near the walls is decreased. Therefore, for the same Knudsen number, the temperature jump for this case is higher than what is observed for the case in which the channel height changes at a constant gas density. The normalized effective thermal conductivity of the argon gas based on the heat flux that is obtained by implementation of the Irving-Kirkwood method reveals that the two cases give the same normalized effective thermal conductivity. For the constant density case, the total thermal resistance increases as the Knudsen number decreases while for the constant height case, it reduces considerably. Meanwhile, it is observed that regardless of the method used to change the Knudsen number, a considerable portion of the total thermal resistance refers to interfacial and wall force field thermal resistance even for near micrometer-sized channels. It is shown that while the local thermal conductivity in the near-wall region strongly depends on the gas density, the wall force field leads to a reduced local thermal conductivity as compared to the bulk region.

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Section: Introductionmentioning

confidence: 99%

Interplay of confinement and density on the heat transfer characteristics of nanoscale-confined gas

Rabani

Heidarinejad

Harting

et al. 2018

International Journal of Heat and Mass Transfer

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“…A tolerance stack-up in manufacturing processes and the head protrusion induced by ambient temperature and write current can generate the flying height variations. To achieve the target head-media clearance during writing and reading processes, a slider that consists of a heater near the read/write elements is applicable for adjusting the head-media clearance [1][2][3][4][5]. The heating generated in the heater induces head deformation called heater-induced head protrusion (H-IHP).…”

Section: Introductionmentioning

confidence: 99%

A study of head instabilities in TMR sensors using in high density perpendicular magnetic recoding systems

Tongsomporn¹,

Afzulpurkar

Sitthisak

2009

International Journal of Applied Electromagnetics and Mechanics

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We did an experimental study to examine head instabilities and noise of tunneling magnetoresistance (TMR) sensors using in high-density perpendicular recording systems. It found that the instability signatures on the transfer curves could be categorized into two groups; permanent magnet/free layer (PM/FL) failure and synthetic antiferromagnetic layers/antiferromagnetic layer (SAF/AFM) failure. The thermal-mechanical stress from the adaptive flying height (AFH) heater as well as head-disk interaction potentially degrades PM resulting in the reduction of the FL stabilizing field, therefore TMR ratio and signal increases. The non-uniformity of PM remnant magnetization and the switching of PM grains especially near the edge potentially degrade the biasing field. Scanning electron microscope images of these weak heads show rough surface and scratches close to the active area of read sensor. The deep scratches by particles in the head-disk interaction and shallow scratches by the slider lapping process is a potential cause to degrade PM. In another group, the thermal-mechanical stress from AFH heater potentially reduces the exchange-bias field and thermal stability of SAF/AFM layers allowing partial flipping of SAF edge magnetization, consequently it induces voltage fluctuations and hysteresis loops in the transfer curves.

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“…In this article, we will not discuss the sealing related problems, but focus our attention on the flying and thermal performances of a thermal actuated slider at the inert gas filled HDI. Although there are some previous studies on the effects of gas composition on the slider flying height [3][4][5] and performances of thermally activated heads [6][7][8][9][10], the researches in these areas are still not enough. We will perform a series of numerical simulations to study the slider's flying characteristics in a disk drive filled with various gases.…”

Section: Introductionmentioning

confidence: 99%

Inert Gas Filled Head–Disk Interface for Future Extremely High Density Magnetic Recording

Zhou

Liu

et al. 2008

Tribol Lett

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Inert gas filled head-disk interface (HDI) is a possible solution in reducing the magnetic spacing between the magnetic head and the magnetic media for achieving further increased recording density of a magnetic recording system. This article investigated the flying and thermal performances of a thermal actuated slider at inert gas filled HDI by using a couple-field analysis method which consists of a finite element model of the entire slider, an air bearing model based on the generalized lubrication equation and a heat transfer model which incorporates various molecular dynamics models and considers temperature effects. The simulation studies showed that the variation of gap flying height (FH) with the heater power in the inert gas is quite similar to that in air. It is also found that the slider's thermal actuation efficiency in helium is slightly better than those in argon and air. However, the temperature effects in a fully sealed drive are totally different to those in an open drive. As a result, the inert gas filled HDI normally requires a larger thermal actuation stroke due to the temperature effects in a fully sealed drive.

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Flying-height reduction of magnetic-head slider due to thermal protrusion

Cited by 74 publications

References 5 publications

Interplay of confinement and density on the heat transfer characteristics of nanoscale-confined gas

Interplay of confinement and density on the heat transfer characteristics of nanoscale-confined gas

A study of head instabilities in TMR sensors using in high density perpendicular magnetic recoding systems

Inert Gas Filled Head–Disk Interface for Future Extremely High Density Magnetic Recording

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