Extendibility of traditional perpendicular magnetic recording for hard disk drives

Model scratches of the size found in hard disk drives are produced under controlled conditions at a series of applied loads on both longitudinal magnetic recording (LMR) media and perpendicular magnetic recording (PMR) media using a diamond tip. The scratches are created at low speed, eliminating thermal considerations from the interpretation of the media response. Nanoindentations are produced as well. The scratches and indentations are characterized by atomic force microscope (AFM), magnetic force microscope (MFM), and also by the same magnetic reader and writer used in an integrated hard disk drive (HDD). A comparison of the response of PMR and LMR media shows the PMR media to have larger scratches and greater magnetic signal degradation than LMR media for a given scratch load. The extent of magnetic damage, as measured by MFM, is greater than the extent of surface mechanical damage, as measured by AFM. Analysis of scratches using the HDD reveals that the magnetic damage is irreversible and permanent damage in magnetic layer, which is confirmed by cross section transmission electron microscope image. The experiments reveal the mechanism for magnetic scratch erasure in the absence of thermal effects. This understanding is expected to lead to improved designs for mechanical scratch robustness of next-generation PMR media.

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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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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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ChemInform Abstract: Development of High Density Magnetic Recording Media for Hard Disk Drives: Materials Science Issues and Challenges

ChemInform ◽

10.1002/chin.201030274 ◽

2010 ◽

Vol 41 (30) ◽

pp. no-no

Author(s):

G. W. Qin ◽

Y. P. Ren ◽

N. Xiao ◽

B. Yang ◽

L. Zuo ◽

...

Keyword(s):

Magnetic Recording ◽

Materials Science ◽

Hard Disk Drives ◽

Hard Disk ◽

High Density ◽

Recording Media ◽

Disk Drives ◽

Magnetic Recording Media ◽

High Density Magnetic Recording

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Load/Unload Systems With Multiple Flying Height States

Journal of Tribology ◽

10.1115/1.1576426 ◽

2004 ◽

Vol 126 (2) ◽

pp. 367-371 ◽

Cited By ~ 7

Author(s):

M. Suk ◽

O. Ruiz ◽

D. Gillis

Keyword(s):

Magnetic Recording ◽

Hard Disk Drives ◽

Hard Disk ◽

Flying Height ◽

Critical Parameters ◽

Disk Drives ◽

Unloaded State ◽

Recording Process ◽

Loaded State ◽

Proper Operation

In hard disk drives that utilize load/unload technology, the slider loads onto the disk from hundreds of microns away before the slider settles into the designed flying height. Due to the forces acting on the slider after the transition from the unloaded state to the fully loaded state, the resulting flying height of the slider may be about two orders of magnitude higher than the intended nominal flying height. Under certain circumstances, the slider may never reach the nominal flying height required for proper operation of the magnetic recording process. In this paper, the existence of multiple flying heights is demonstrated and verified both by experimentation and simulation. The effect of some of the critical parameters is also identified by both methods. We show that necessary care must be taken to avoid unwanted loading sequences where the system may be unable to store or retrieve data.

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HAMR HDD Shock Responses

ASME 2013 Conference on Information Storage and Processing Systems ◽

10.1115/isps2013-2896 ◽

2013 ◽

Cited By ~ 1

Author(s):

Lidu Huang ◽

Kenzi Suzuki ◽

Fu-Ying Huang ◽

Toshiki Hirano ◽

Barry Stipe

Keyword(s):

Solid State ◽

Laser Diode ◽

Magnetic Recording ◽

Hard Disk Drives ◽

Hard Disk ◽

Cost Advantage ◽

Disk Drives ◽

Solid State Drive ◽

Lift Off ◽

Operational Shock

Heat assisted magnetic recording (HAMR) and slim mobile hard disk drives (HDD) are being developed parallelly to maintain cost advantage over the solid state drive (SSD). Operational shock and non-operational shock capabilities are seriously challenged for the slim HDDs due to reduced stiffness (thickness). It is worse for slim HAMR drives due to additional laser diode (LD) and other necessities being added on slider. Shock tests are part of the key performance matrices that must be passed in HDD reliability tests, and the concerns for HAMR mobile drives are, 1) slider lift-off G-level degradation during op-shock, and 2) LD back-to-back hitting during non-operational shock. We studied a few potential HAMR HGA designs, also analyzed a design that improves drive op-shock performances.

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