Effects of Molecularly Thin Liquid Lubricant Films on Slider Hysteresis Behavior in Hard Disk Drives

Tagawa, Norio; Mori, Atsunobu; Senoue, Ken

doi:10.1115/ijtc2006-12062

Cited by 9 publications

(15 citation statements)

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“…A schematic representation of the experimental setup and measurement system, which consists of an air bearing spindle, a slider mount fixture, an LDV unit, an AE sensor, and a slider load/unload mechanism, is shown in Fig. 3 [6]. The laser spot of the LDV unit was focused on the trailing edge of the slider, and the spot size was *40 lm.…”

Section: Procedures For Studying the Slider Touchdown And Takeoff Hystmentioning

confidence: 99%

Conformation and Fundamental Properties of Novel Lubricant TA-30 for Near Contact Magnetic Recording

Tagawa

Tani

2010

Tribol Lett

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A novel perfluoropolyether (PFPE) lubricant called TA-30 has been developed recently. We investigate the conformation of TA-30 on diamond-like carbon (DLC) thin films, by attempting the direct observation of a lubricant film by atomic force microscopy (AFM) using a fluoride probe. We investigate the fundamental properties of a TA-30 lubricant film, such as its spreading characteristics, and the film thickness dependence of surface energy. Considering these experimental results, we conclude that the conformation of TA-30 is considerably different from that of conventional Z-tetraol2000 whose molecular height is 1.7 nm and which was adsorbed on the DLC surface with the random coil. The TA-30 molecules are adsorbed rigidly to the DLC surface with double layers. The thickness of the first TA-30 layer is *0.9 nm (similar to diameter of the PFPE backbone) and that of the second layer from the DLC surface is 1.4 nm. Since TA-30 has a lower film thickness than Z-tetraol2000 on the DLC surface, it can have two layers, even if the film thickness is approximately of the order of 1 nm, whereas Z-tetraol2000 does not cover the DLC surface and does not form the complete first layer. In addition, we conduct slider touchdown and takeoff hysteresis tests by using TA-30 and Z-tetraol2000. It is confirmed that the use of TA-30 can improve the head-disk interface (HDI) reliability at lowfly-height conditions.

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Section: Procedures For Studying the Slider Touchdown And Takeoff Hystmentioning

confidence: 99%

Conformation and Fundamental Properties of Novel Lubricant TA-30 for Near Contact Magnetic Recording

Tagawa

Tani

2010

Tribol Lett

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“…As magnetic recording densities have increased, the HDI spacing of the head has been reduced to such an extent that the effect of these ultra-thin lubricant films has become more apparent. However, a critical issue in achieving such an ultralow spacing is the dynamic instability of the HDI due to interactions during slider-lubricant contact, that is, the experimentally observed slider hysteresis (Tagawa et al 2007). Figure 1 shows a schematic of the hysteresis of the flying sliders.…”

Section: Introductionmentioning

confidence: 97%

Effect of humidity on the interactions between probes and ultra-thin liquid lubricant films in an environmentally controlled atomic force microscope

2009

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To achieve a magnetic recording density of 1 Tb/in 2 , the required head-disk spacing is expected to be less than 2-3 nm. However, a critical issue in achieving such an ultra-low spacing is the dynamic instability of the head-disk interface (HDI), that is, the experimentally observed hysteresis of the flying sliders. It is important to clarify the interactive forces between the sliders and disk surfaces in a nanometer HDI. In addition, the adhesive forces between the thermally protruding magnetic head writer pole tip, which exists in the most commercially available recording head, and the lubricant film have also become very important. Therefore, in this study, the interactions between the probes of an environmentally controlled atomic force microscope (AFM) and ultra-thin liquid lubricant films were studied as a model experiment, resulting in the acquisition of fundamental knowledge related to the adhesive forces as well as the slider hysteresis. Subsequently, the effect of humidity on the force curve characteristics was investigated by varying the lubricant film thickness. As a result, it was found that the probe touchdown occurred earlier as the humidity increased, with its driving force suggested to be the force of the lubricant meniscus formed on the AFM probe. The probe touchdown occurred earlier for lubricants with a higher mobility. The adhesive force gradually increased with the humidity and was at its minimum for a one monolayer film thickness, independent of the lubricant materials. On the other hand, the elongation of the lubricant meniscus increased with the humidity. Therefore, the probe takeoff occurred later as the humidity increased. Accordingly, the hysteresis increased with the humidity and was mainly dependent on the elongation of the meniscus.

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“…It is reported that the hysteresis is related to the lubricant thickness and the percentage of mobile lubricant (Ambekar et al 2005;Demczyk et al 2005;Tagawa et al 2005). In general, thicker lubricant seems to have lower takeoff speed and lower touchdown speed (Ambekar et al 2005), or lower takeoff pressure and lower touchdown pressure (Demczyk et al 2005;Tagawa et al 2007). One possible explanation is that the lubricant may influence the Hamaker constant for the intermolecular force, and therefore the takeoff and touchdown performances are changed.…”

Section: Discussion On Short Range Forces and Lubricant Interactionmentioning

confidence: 91%

Contact recording review

Hua

Liu

et al. 2010

Microsyst Technol

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Various contact recording technologies for hard disk drives are reviewed. The advantages and disadvantages of each approach to contact recording are analyzed. Experimental detection methods and simulation models for the contact force are introduced. Some important technologies related to contact recording are addressed. The effects of lubricant and the short range forces on contact recording are discussed, and the dynamic flying characteristics of a slider with spherical pad at trailing edge are studied. It is suggested that a thermal protrusion slider with a spherical pad at the trailing edge may be a possible approach for the success of contact recording.

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Effects of Molecularly Thin Liquid Lubricant Films on Slider Hysteresis Behavior in Hard Disk Drives

Cited by 9 publications

References 0 publications

Conformation and Fundamental Properties of Novel Lubricant TA-30 for Near Contact Magnetic Recording

Conformation and Fundamental Properties of Novel Lubricant TA-30 for Near Contact Magnetic Recording

Effect of humidity on the interactions between probes and ultra-thin liquid lubricant films in an environmentally controlled atomic force microscope

Contact recording review

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