Thermal Fly-Height Controlled Glide for Disk Defect Detection and In-Situ Defect Size Estimation for Disk Drives

2013 ◽  
Author(s):  
Aravind N. Murthy ◽  
Karl A. Flechsig ◽  
Wes Hillman ◽  
Keith Conard ◽  
Remmelt Pit
Keyword(s):  
Hard Disk Drives ◽  
Sem Analysis ◽  
Disk Drives ◽  
Size Estimation ◽  
Optical Surface ◽  
Force Microscopy ◽  
Height Control ◽  
Atomic Force ◽  
Fly Height

Current hard disk drives (HDD’s) use thermal fly-height control (TFC) during read/write operations. In this study, we use TFC technology during the disk glide process to determine sub-5nm height defects. We also utilize TFC to measure the height of the defect during glide operation. Addtionally, we magnetically mark the disk locations where defects are detected for further post-processing of the defects using optical surface analysis (OSA), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The defect height estimation during the glide was confirmed to be accurate by AFM and SEM analysis. Finally, we will present the TFC glide sensitivity showing capability of detecting smaller defects than conventional non-TFC glide technologies.

Temperature Study of Embedded Contact Sensor for HDDS by Using Scanning Thermal Microscopy

2014 ◽  
Author(s):  
Masaru Furukawa ◽  
Junguo Xu ◽  
Jianhua Li ◽  
Kiyoshi Hashimoto ◽  
Makoto Satou
Keyword(s):  
Hard Disk Drives ◽  
Disk Drives ◽  
Scanning Thermal Microscopy ◽  
Height Control ◽  
Head Slider ◽  
Self Bias ◽  
Key Factor ◽  
Contact Sensor ◽  
Sensor Temperature ◽  
Fly Height

An embedded contact sensor (ECS), which is a thermal sensor built into a head slider, has been used for contact detection between the head slider and the disk in hard disk drives. Our previous research showed that ECS could successfully detect pits on the disk and spacing modulation between the head and disk. In this work, the sensor temperature effect caused by self heating and by the thermal fly height control (TFC) heater was studied in a non-flying condition for better understanding ECS. The results showed that the temperature dependency of the TFC heater was 10 times that of ECS self-bias heating. TFC heating is dominant and the key factor in ECS sensitivity to pit detection and spacing monitoring.

Thermal fly-height controlled glide for disk defect detection and defect size estimation for hard disk drives

2014 ◽  
Vol 20 (8-9) ◽  
pp. 1523-1527 ◽  
Author(s):  
Aravind N. Murthy ◽  
Karl A. Flechsig ◽  
Wes Hillman ◽  
Keith Conard ◽  
Remmelt Pit
Keyword(s):  
Defect Detection ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Defect Size ◽  
Disk Drives ◽  
Size Estimation ◽  
Fly Height

An Insight Into the Nonlinear Touchdown Dynamics of TFC Active Slider

2013 ◽  
Author(s):  
Gang (Sheng) Chen ◽  
Jianfeng Xu ◽  
J.-Y. Chang
Keyword(s):  
Nonlinear Dynamics ◽  
Hard Disk Drives ◽  
Disk Surface ◽  
Flying Height ◽  
Disk Drives ◽  
Height Control ◽  
Intermittent Contact ◽  
Fly Height ◽  
Insight Into ◽  
Small Spacing

Storage of 10 Tb/in 2 in hard disk drives within the next decade requires a significant change to reduce the physical spacing as little as 0.25 nm at the read-write transducer location. A lot of tribology issues exist to such a low flying height, the touch down and take off instability and hysteresis, the flying height avalanche, the influences of surface topography and morphology, the lubricant modulation and pick-up, robust air bearing surface and suspension design, just to name a few. Understandings of the complex tribo-dynamics issues in the near contact and contact states are very important to further reduce the flying height. At such a small spacing intermittent contact between the slider and disk surface becomes inevitable and the current MEMS-based thermal fly-height control (TFC) technology needs further improvement to satisfy the future needs. How to control the slider to reduce touchdown instability and eventually eliminate bouncing has been a pressing and challenging research topic. Most of existing work on touchdown dynamics applied conventional nonlinear dynamics theory and spectrum as well as harmonics analysis, which could suffer from the assumptions of small nonlinearity and stationary. This study presents a concurrence plot and Lyapunov exponent analysis which could offer an insight to the problem in the context of contemporary nonlinear dynamics theory.

AFM study of the dynamics of α-alumina surface faceting during high-temperature processing

1995 ◽  
Vol 53 ◽  
pp. 334-335 ◽  
Author(s):  
Michael W. Bench ◽  
Jason R. Heffelfinger ◽  
C. Barry Carter
Keyword(s):  
High Temperature ◽  
Thin Foil ◽  
Sem Analysis ◽  
Conductive Coatings ◽  
Force Microscopy ◽  
Minimal Sample ◽  
Atomic Force ◽  
Formation And Evolution ◽  
High Temperature Processing ◽  
Nominal Surface

To gain a better understanding of the surface faceting that occurs in α-alumina during high temperature processing, atomic force microscopy (AFM) studies have been performed to follow the formation and evolution of the facets. AFM was chosen because it allows for analysis of topographical details down to the atomic level with minimal sample preparation. This is in contrast to SEM analysis, which typically requires the application of conductive coatings that can alter the surface between subsequent heat treatments. Similar experiments have been performed in the TEM; however, due to thin foil and hole edge effects the results may not be representative of the behavior of bulk surfaces.The AFM studies were performed on a Digital Instruments Nanoscope III using microfabricated Si3N4 cantilevers. All images were recorded in air with a nominal applied force of 10-15 nN. The alumina samples were prepared from pre-polished single crystals with (0001), , and nominal surface orientations.

scholarly journals Ultrafine metal-polymer catalysts based on polyconjugated systems for Fisher–Tropsch synthesis

2020 ◽  
Vol 92 (6) ◽  
pp. 977-984
Author(s):  
Mayya V. Kulikova ◽  
Albert B. Kulikov ◽  
Alexey E. Kuz’min ◽  
Anton L. Maximov
Keyword(s):  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Force Microscopy ◽  
Composite Catalysts ◽  
Fe Catalyst ◽  
Atomic Force ◽  
And Function ◽  
Metal Polymer

AbstractFor previously studied Fischer–Tropsch nanosized Fe catalyst slurries, polymer compounds with or without polyconjugating structures are used as precursors to form the catalyst nanomatrix in situ, and several catalytic experiments and X-ray diffraction and atomic force microscopy measurements are performed. The important and different roles of the paraffin molecules in the slurry medium in the formation and function of composite catalysts with the two types of aforementioned polymer matrices are revealed. In the case of the polyconjugated polymers, the alkanes in the medium are “weakly” coordinated with the metal-polymer composites, which does not affect the effectiveness of the polyconjugated polymers. Otherwise, alkane molecules form a “tight” surface layer around the composite particles, which create transport complications for the reagents and products of Fischer-Tropsch synthesis and, in some cases, can change the course of the in situ catalyst formation.

Atomic force microscopy of in situ deformed nickel thin films

1999 ◽  
Vol 353 (1-2) ◽  
pp. 194-200 ◽  
Author(s):  
C. Coupeau ◽  
J.F. Naud ◽  
F. Cleymand ◽  
P. Goudeau ◽  
J. Grilhé
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
Nickel Thin Films ◽  
Atomic Force
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