Effect of Rheology and Slip on Lubricant Deformation and Disk-to-Head Transfer During Heat-Assisted Magnetic Recording (HAMR)

Sakhalkar, Siddhesh V.; Bogy, David B.

doi:10.1007/s11249-018-1100-4

Cited by 9 publications

(1 citation statement)

References 44 publications

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“…For this reason, Sarabi et al [27] considered the lubricant film as a uniform viscoelastic film and employed the lubrication equation for viscoelastic lubrication films presented by Tichy [28] to analyze the evaporation caused by laser spots and the replenishment characteristics of their depleted marks. In addition, Sakhalkar et al [29,30] analyzed the mechanism of transfer of lubricant evaporated from the disk surface to the head surface in HAMR recording using the viscoelastic film equation considering the temperature characteristics of tension and viscosity, and clarified the difference in transfer rate and transfer amount between Z-Tetraol and Z-dol, and the influences of various parameters. However, it is not clear whether these advanced analyses could be experimentally confirmed and the uniform viscoelastic property could maintain the wear reliability of the head.…”

Section: Diffusion Characteristics Of Sub-nanometer Lubricant Filmmentioning

confidence: 99%

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Ono

2024

Lubricants

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This review presents a series of studies which have demonstrated that the diffusion characteristics of rarefied mobile lubricant films used in modern magnetic disks can be evaluated by a novel diffusion theory based on continuum mechanics, and that the meniscus force of the rarefied film is the major interaction force at the head-disk interface. The limitations of the conventional diffusion and disjoining pressure equations are first shown, and diffusion and disjoining pressure equations for rarefied liquid films are proposed, showing that the diffusion coefficient is in good agreement with the experiment. The experiment, in which glass spheres with radii of 1 and 2 mm collided with magnetic disks of different film thicknesses, showed that attraction similar to the pull-off forces of a static meniscus was measured only at the separation. Furthermore, mathematical analysis of the elastic meniscus contact between a sphere and a plane with a submonolayer liquid film showed that the maximum adhesion force is equal to the meniscus pull-off force and that the contact characteristics become similar to those of the JKR theory as the liquid film thickness decreases. A basic physical model of submonolayer liquid film is also proposed to justify the continuum mathematical equations.

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Section: Diffusion Characteristics Of Sub-nanometer Lubricant Filmmentioning

confidence: 99%

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Ono

2024

Lubricants

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A Numerical Simulation of PFPE Lubricant Kinetics in HAMR Air Bearing

Tom,

Cheng,

Bogy

2024

Tribol Lett

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This report investigates the kinetics of lubricant molecules in the HAMR air bearing to understand the initiation and growth of PFPE contamination on the head surface. The collisions with the air bearing induce three forces—drag, thermophoresis, and lift. Of these, we find that lift forces are negligible. Then, a sensitivity analysis of the remaining two forces reveals the conditions where they dominate. Further, a hybrid simulation strategy is utilized to track their movements. The results show that the contaminations (smear) highly depend on the interplay between the thermophoresis and drag forces. We then explain the mechanism of the formation of the various observed patterns. Finally, we offer some recommendations to exploit the air bearing to contain smear on the head.

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