Lubricant Additives for Magnetic Recording Disk Drives

The materials used in magnetic recording heads have recently received a tremendous amount of attention. This has been the result of a fortunate set of circumstances. Ever-increasing demands for information storage, especially for graphics-intensive applications, have necessitated unprecedented increases in disk-drive areal densities. Combined with this are recent discoveries in the area of magnetoresistive materials, enabling the design and fabrication of much more sensitive recording heads. The end result is a flurry of activity that has come to dominate the field of magnetics. This article will explore choices for magnetoresistive read head materials, with an emphasis on the materials challenges.The recording heads that are used in high-performance disk drives typically consist of separate magnetoresistive read and inductive write heads (see Figure 1) where previously a single inductive head performed both functions. Separation of the two heads allows each to be optimized for their individual function, an essential factor in enabling disk drives to contain gigabytes of storage. The write head is the simpler of the two, consisting of a U-shaped ferromagnet surrounding a set of coils. The ends of the ferromagnet are the magnetic poles defining the write gap. When current passes through the coils, a field bridges the gap, setting the orientation of the magnetization in the media. Information is stored by changing the polarity of the current in order to write a pattern of magnetic domains in the media. The materials used in write poles will be reviewed in the section, Write Head Materials.

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6PM2-C-3 Lubricant depletion due to laser heating in thermally assisted magnetic recording in hard disk drives

The Proceedings of the Symposium on Micro-Nano Science and Technology ◽

10.1299/jsmemnm.2013.5.165 ◽

2013 ◽

Vol 2013.5 (0) ◽

pp. 165-166

Author(s):

Norio Tagawa ◽

Hiroshi Tani ◽

Shinji Koganezawa

Keyword(s):

Magnetic Recording ◽

Laser Heating ◽

Hard Disk Drives ◽

Hard Disk ◽

Disk Drives ◽

Lubricant Depletion ◽

Thermally Assisted Magnetic Recording

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Extendibility of traditional perpendicular magnetic recording for hard disk drives

Journal of Applied Physics ◽

10.1063/1.3563095 ◽

2011 ◽

Vol 109 (7) ◽

pp. 07B774

Author(s):

James A. Bain ◽

B. V. K. Vijaya Kumar ◽

Yu Cai ◽

Seungjune Jeon ◽

Ken Mai ◽

...

Keyword(s):

Magnetic Recording ◽

Hard Disk Drives ◽

Hard Disk ◽

Disk Drives ◽

Perpendicular Magnetic Recording

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Ultrahigh-Density Recording Technologies

MRS Bulletin ◽

10.1557/s0883769400036319 ◽

1996 ◽

Vol 21 (9) ◽

pp. 17-22 ◽

Cited By ~ 80

Author(s):

Mark H. Kryder

Keyword(s):

Data Storage ◽

Magnetic Recording ◽

Computer Systems ◽

Hard Disk Drives ◽

Hard Disk ◽

Time Frame ◽

Optical Recording ◽

Disk Drives ◽

Slowing Down ◽

Long Term Storage

Magnetic recording and optical recording are the major technologies used to provide long-term storage of information in today's computer systems. Magnetic recording has been used for data storage in computer systems for over 40 years, and the advances in technology that have occurred in that time frame are nothing short of phenomenal. One might expect that after 40 years of dominance, the rate of progress in magnetic recording would be slowing down and that other technologies would be moving in to replace it. However rather than slowing down its rate of progress, magnetic recording is now advancing at a faster rate than at any time in the past. Magnetic hard-disk drives represent the largest segment of the data-storage business, and the number of hard-disk drives sold is increasing at about 20% per year. Tape drives continue to enjoy a very substantial market and are also advancing at a rapid pace while flexible disk drives continue to appear in every personal computer sold and have recently increased capacity by nearly two orders of magnitude.Optical recording was introduced into the marketplace in 1989 and has secured a significant market. However thus far, optical recording has primarily found new market niches, rather than being directly competitive with magnetic recording. CD-ROMs are widely used for the distribution of prerecorded information—a business that is now comparable in size to the magnetic-tape-drive business. On the other hand, erasable, optical drives, which were first introduced in 1989, have not had nearly as much success and have much smaller markets than either magnetic hard drives or tape drives.

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Plasmonic near-field transducer for heat-assisted magnetic recording

Nanophotonics ◽

10.1515/nanoph-2014-0001 ◽

2014 ◽

Vol 3 (3) ◽

pp. 141-155 ◽

Cited By ~ 92

Author(s):

Nan Zhou ◽

Xianfan Xu ◽

Aaron T. Hammack ◽

Barry C. Stipe ◽

Kaizhong Gao ◽

...

Keyword(s):

Magnetic Recording ◽

Near Infrared ◽

Near Field ◽

Hard Disk Drives ◽

Plasmonic Nanostructures ◽

Disk Drives ◽

Limited Region ◽

Heat Assisted Magnetic Recording ◽

Self Heating ◽

Infrared Frequencies

AbstractPlasmonic devices, made of apertures or antennas, have played significant roles in advancing the fields of optics and opto-electronics by offering subwavelength manipulation of light in the visible and near infrared frequencies. The development of heat-assisted magnetic recording (HAMR) opens up a new application of plasmonic nanostructures, where they act as near field transducers (NFTs) to locally and temporally heat a sub-diffraction-limited region in the recording medium above its Curie temperature to reduce the magnetic coercivity. This allows use of very small grain volume in the medium while still maintaining data thermal stability, and increasing storage density in the next generation hard disk drives (HDDs). In this paper, we review different plasmonic NFT designs that are promising to be applied in HAMR. We focus on the mechanisms contributing to the coupling and confinement of optical energy. We also illustrate the self-heating issue in NFT materials associated with the generation of a confined optical spot, which could result in degradation of performance and failure of components. The possibility of using alternative plasmonic materials will be discussed.

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Baseline Popping Detection and Correction Algorithms for Perpendicular Magnetic Recording System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.979.50 ◽

2014 ◽

Vol 979 ◽

pp. 50-53

Author(s):

Piya Kovintavewat ◽

Santi Koonkarnkhai

Keyword(s):

Magnetic Recording ◽

System Performance ◽

Hard Disk Drives ◽

Recording System ◽

Disk Drives ◽

Threshold Detector ◽

Perpendicular Magnetic Recording ◽

The Third ◽

Averaging Filter ◽

Better Than

Hard disk drives (HDDs) employ the magneto-resistive (MR) head to sense the change in magnetic flux via the transitions of magnetization pattern, resulting in a readback signal. Thus, head instability plays an important role on the reliability of HDDs because it can deteriorate the system performance considerably. Baseline popping (BLP) is one of the crucial problems caused by the head instability, whose effect can distort the readback signal to the extent of causing a sector read failure. This paper proposes three BLP detection and correction algorithms for a perpendicular magnetic recording (PMR) system. Specifically, to suppress the BLP effect experienced in the readback signal, the first algorithm is based on an averaging filter and a threshold detector; the second one relies on the estimated BLP signal obtained from a linear curve fitting technique; and finally the third one uses two sequence detectors running in parallel. Experimental results indicate that the third algorithm performs better than the other schemes because it can detect and correct the BLP better than the others, especially when the peak BLP amplitude is large.

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Thermal Lagging of Multilayered Structure in Heat-Assisted Magnetic Recording Systems

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4046022 ◽

2020 ◽

Vol 12 (3) ◽

Author(s):

Jian Su ◽

Tingting Tang ◽

Ruixin Lu ◽

Peng Yu

Keyword(s):

Temperature Gradient ◽

Thermal Resistance ◽

Magnetic Recording ◽

Heat Sink ◽

Hard Disk Drives ◽

Hard Disk ◽

Interfacial Thermal Resistance ◽

Disk Drives ◽

Horizontal Temperature Gradient ◽

Heat Assisted Magnetic Recording

Abstract In the present study, we numerically investigate the thermal lagging behavior on the hard disk drives in heat-assisted magnetic recording systems via the optical absorption model. The influences of overcoats, laser radius, relative scanning speed, interfacial thermal resistance, and the heat sink layer on the thermal lagging behavior are studied in detail. It is found that the thermal lagging distance, i.e., the horizontal distance between the location of the maximum temperature and the laser center, increases with an increment of speed and/or radius of the laser spot. The overcoats, the interfacial thermal resistance, and the heat sink layer have negligible effects on the lagging distance. Thus, the multilayered disk can be simplified as a single-layer disk for investigating thermal lagging distance. Meanwhile, the horizontal temperature gradient varies with these factors. Different overcoats result in different horizontal temperature gradient owing to the difference of in-plane thermal diffusivity. A laser with a smaller radius or a slower speed leads to a higher horizontal temperature gradient. The thermal resistance influences the horizontal temperature gradient insignificantly. This study may provide useful information for the design of hard disk drives for heat-assisted magnetic recording technologies.

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