Impact of Touchdown Detection on Bit Patterned Media Robustness

2013 ◽  
Author(s):  
Jia-Yang Juang ◽  
Kuan-Te Lin
Keyword(s):  
Areal Density ◽  
Flying Height ◽  
Head Disk Interface ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Disk Interface ◽  
Recording Process ◽  
Friction Temperature ◽  
The Media ◽  
The Impact

Bit patterned media (BPM) is considered as a revolutionary technology to enable further increase of areal density of magnetic recording beyond 1 Tbits/in2 [1]. Implementing BPM technology, however, significantly increases the complexity of the recording process, but also poses tremendous tribological challenges on the head-disk interface (HDI) [2]. One of the major challenges facing BPM is touchdown detection by thermal flying-height control (TFC), in which a minute heater located near the read/write transducers is used to thermally protrude a small portion of the slider into contact with the disk, and the contact is then detected by directly or indirectly measuring the friction, temperature rise or vibration caused by the contact [3]–[7]. Most recording heads rely on touchdown detection to achieve a desired flying height (FH), which approaches sub-1-nm regime for many of today’s commercial drives. As a result sensitive and accurate touchdown detection is of critical importance for a reliable head-disk interface by reducing contact duration and unnecessary interaction between the slider and the disk. However, the impact of touchdown on the mechanical robustness of the media has not been properly studied.

scholarly journals Micromagnetic Simulation of L10-FePt-Based Exchange-Coupled-Composite-Bit-Patterned Media with Microwave-Assisted Magnetic Recording at Ultrahigh Areal Density

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1264
Author(s):  
Pirat Khunkitti ◽  
Naruemon Wannawong ◽  
Chavakon Jongjaihan ◽  
Apirat Siritaratiwat ◽  
Anan Kruesubthaworn ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Areal Density ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Microwave Assisted ◽  
The Media ◽  
5 Ghz ◽  
Exchange Coupled Composite

In this work, we propose exchange-coupled-composite-bit-patterned media (ECC-BPM) with microwave-assisted magnetic recording (MAMR) to improve the writability of the magnetic media at a 4 Tb/in2 recording density. The suitable values of the applied microwave field’s frequency and the exchange coupling between magnetic dots, Adot, of the proposed media were evaluated. It was found that the magnitude of the switching field, Hsw, of the bilayer ECC-BPM is significantly lower than that of a conventional BPM. Additionally, using the MAMR enables further reduction of Hsw of the ECC-BPM. The suitable frequency of the applied microwave field for the proposed media is 5 GHz. The dependence of Adot on the Hsw was additionally examined, showing that the Adot of 0.14 pJ/m is the most suitable value for the proposed bilayer ECC-BPM. The physical explanation of the Hsw of the media under a variation of MAMR and Adot was given. Hysteresis loops and the magnetic domain of the media were characterized to provide further details on the results. The lowest Hsw found in our proposed media is 12.2 kOe, achieved by the bilayer ECC-BPM with an Adot of 0.14 pJ/m using a 5 GHz MAMR.

Soft Particle-Induced Magnetic Erasure Without Physical Damage to the Media

2007 ◽  
Vol 129 (4) ◽  
pp. 729-734 ◽  
Author(s):  
M. Roy ◽  
J. L. Brand
Keyword(s):  
Frictional Heating ◽  
Mechanical Damage ◽  
Soft Particle ◽  
Head Disk Interface ◽  
Physical Damage ◽  
Component Level ◽  
Disk Interface ◽  
Permanent Loss ◽  
The Media ◽  
The Impact

With ever increasing areal density, interactions of particles with a head-disk interface become an ever more important factor impacting the drive reliability. Although particles trapped between the head and the disk could induce mechanical damage to the media resulting in permanent loss of data, data loss has also been observed without any obvious signs of physical damage to the media. We devised a component-level test to study this mode of data erasure on both glass and aluminium media. Our data indicate that the frictional heating associated with contact force between the particle and the disk could lead to permanent loss of data. In addition, we performed investigations to study the impact of air bearing design features, load/unload mechanism, and particle number density on the head disk interface.

Molecular Dynamics Simulation of Lubricant Transfer Between Slider and Bit Patterned Disk

2017 ◽  
Author(s):  
Wenping Song ◽  
Shimin Yu ◽  
Deng Pan ◽  
Qingkang Liu ◽  
Longqiu Li
Keyword(s):  
Molecular Dynamics ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Flying Height ◽  
Spring Model ◽  
Lubricant Thickness ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Lubricant Transfer ◽  
Disk Interface

A modified coarse-grained, bead-spring model for lubricant transfer from a bit patterned media (BPM) disk to a slider is developed using molecular dynamics (MD). The lubricant transfer at slider/BPM disk interface is compared with that at slider/conventional disk interface. In addition, the effect of lubricant thickness and slider flying height is investigated.

scholarly journals The Head-Disk Interface Roadmap to an Areal Density of Tbit/in2

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Bruno Marchon ◽  
Thomas Pitchford ◽  
Yiao-Tee Hsia ◽  
Sunita Gangopadhyay
Keyword(s):  
Hard Disk Drives ◽  
Rotating Disk ◽  
Areal Density ◽  
Disk Surface ◽  
Inert Atmosphere ◽  
Annual Growth Rate ◽  
Head Disk Interface ◽  
Bit Patterned Media ◽  
Disk Interface ◽  
Compound Annual Growth Rate

This paper reviews the state of the head-disk interface (HDI) technology, and more particularly the head-medium spacing (HMS), for today’s and future hard-disk drives. Current storage areal density on a disk surface is fast approaching the one terabit per square inch mark, although the compound annual growth rate has reduced considerably from ~100%/annum in the late 1990s to 20–30% today. This rate is now lower than the historical, Moore’s law equivalent of ~40%/annum. A necessary enabler to a high areal density is the HMS, or the distance from the bottom of the read sensor on the flying head to the top of the magnetic medium on the rotating disk. This paper describes the various components of the HMS and various scenarios and challenges on how to achieve a goal of 4.0–4.5 nm for the 4 Tbit/in2density point. Special considerations will also be given to the implication of disruptive technologies such as sealing the drive in an inert atmosphere and novel recording schemes such as bit patterned media and heat assisted magnetic recording.

Impact of Pattern Media Topography on the Tribology of Head-Disk Interfaces

2013 ◽  
Author(s):  
C. Mathew Mate ◽  
Z. Liu ◽  
D. Kercher ◽  
O. Ruiz ◽  
K. Rubin ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Disk Drive ◽  
Continuous Media ◽  
Flying Height ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Disk Drive Industry ◽  
The Impact

Bit patterned media (BPM) is being pursued by the disk drive industry as a way of extending magnetic recording densities beyond 1 Tbits/in2 [1]. As the patterned topography of an unplanarized BPM disk generates a tribology quite different than smooth, continuous media, it is important to assess how this topography will impact the tribology of head-disk interfaces (HDI). In this paper, we quantify the impact of BPM topography on flying height modulation.

Analysis of Stresses Induced by Dynamic Load Head-Disk Contacts

1999 ◽  
Vol 122 (1) ◽  
pp. 233-237 ◽  
Author(s):  
Ta-Chang Fu ◽  
David B. Bogy
Keyword(s):  
Dynamic Load ◽  
Maximum Stress ◽  
Radius Of Curvature ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Impact Stress ◽  
Dual Channel ◽  
Average Maximum ◽  
The Impact ◽  
Maximum Contact

The dynamic load head-disk contact induced impact stress was studied. A dual channel LDV was used to measure the head-disk relative motion during impact, and an analytical model incorporating the Hertz theory of impact was developed to quantitatively estimate the impact induced contact force and stress based on the LDV-measured results. 70 percent sliders were used in order to compare the results with our previous study. From the estimated maximum contact stresses and the results of our previous study, it was found that when the average maximum stress was 511 MPa, the head-disk interface did not show any damage after 100,000 cycles of repeated head-disk impacts. When the average maximum stress was 880 MPa, however, 100,000 repeated head-disk impacts caused significant wear of the disk’s overcoat even though a single impact did not cause any observable damage. From the analysis it can be seen that a lower head-disk impact velocity and/or a larger radius of curvature at the contacting corner of the slider result in a smaller head-disk impact stress on the disk. Based on the analyses, we estimated the radius of curvature needed for a 50 percent (Nano) slider and a 30 percent (Pico) slider to have at least 100,000 cycles of dynamic load head-disk interface durability. Such radius of curvature can be realized, for example, by edge-blending the sliders. [S0742-4787(00)02901-5]

Sign in / Sign up

Export Citation Format

Share Document