Simulation of Contact at Head and Multilayer Disk Interface Under Quasi-Static Condition

2016 ◽  
Author(s):  
Ao Hongrui ◽  
Han Zhiying ◽  
Zhang Kai ◽  
Jiang Hongyuan
Keyword(s):  
Normal Load ◽  
Static Condition ◽  
Flying Height ◽  
Lubricant Layer ◽  
Magnetic Storage ◽  
Multilayer Thin Film ◽  
Head Disk Interface ◽  
Principal Stresses ◽  
Disk Interface ◽  
Von Mises

The reduction of head-media separation (HMS) results in a decreased flying height. Consequently, the contact probability between the slider and the lubricant layer or hard overcoat surface on the disks will increase greatly. Therefore, investigating the contact stress of the disk is vital for improving the reliability of the head disk interface. In this study, a rigid hemisphere sliding over a multilayer thin film half-space is implemented to simulate the contact between the recording slider and the magnetic storage multilayer disk under the quasi-static condition. The effects of different parameters such as normal load, friction coefficient and radius of slider on the von Mises, shear and principal stresses in the multilayer system are analyzed by using finite element method (FEM).

scholarly journals Investigations of Adhesion under Different Slider-Lube/Disk Contact States at the Head–Disk Interface

2020 ◽  
Vol 10 (17) ◽  
pp. 5899
Author(s):  
Yuyan Zhang ◽  
Ling Jiang ◽  
Weixu Yang ◽  
Chenbo Ma ◽  
Qiuping Yu
Keyword(s):  
Disk Drive ◽  
Adhesive Contact ◽  
Flying Height ◽  
Lubricant Layer ◽  
Repulsive Interaction ◽  
Head Disk Interface ◽  
Negative Effects ◽  
Disk Interface ◽  
Static Contact ◽  
Key Factor

Adhesion is the key factor influencing the failure of the hard disk drive operating under ultra-low flying height. In order to mitigate the negative effects of adhesion at the head–disk interface (HDI) and promote further development of the thermal flying height control (TFC) technology, an adhesive contact model based on the Lifshitz theory accounting for the thermal protrusion (TP) geometry of TFC slider, the layered structures of the head and disk, and the operation states of the slider was proposed to investigate the static contact characteristics at the HDI. The simulation results demonstrated the undesirable unstable regions during the transitions between different operation states and the necessity of applying TFC technology. The reduction in the head–media spacing (HMS) was found to be achieved by properly increasing the TP height, decreasing the thickness of the lubricant layer or the thickness of the diamond–like carbon (DLC) layer during the flying state or the TP–lube contact state. At the TP–DLC contact regime, the attractive interaction was stronger than other states, and the strong repulsive interaction made the HMS difficult to be further reduced through the increase in the TP height or the decrease in the lubricant thickness.

Simulation of Contact Behavior of the Thin Film of Hard Disk at Head/Disk Interface

2011 ◽  
Vol 287-290 ◽  
pp. 2339-2342
Author(s):  
Hong Rui Ao ◽  
Deng Pan ◽  
Hong Yuan Jiang
Keyword(s):  
Thin Film ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Hertzian Contact ◽  
Von Mises Stress ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Slider Motion ◽  
Von Mises ◽  
Layered Thin Film

The contact at head/disk interface in hard disk drives subject to an external shock has been studied using the finite element method. A rigid cylinder moving over a two-layered thin film was implemented to simulate the contact between the recording slider and the disk. The effects of different friction coefficients on the von Mises stress of two-layered thin film were investigated. The relation between pressed depth and width of deformation has been obtained. Results show that the amplitude decreases with increase of friction coefficient while the period of slider motion is diminution. In addition, the stress distribution fits Hertzian contact theory.

Effect of Head–Disk Interface Biasing and Relative Humidity on Wear of Thermal Flying Height Control Sliders

2017 ◽  
Vol 65 (2) ◽  
Author(s):  
Liane M. Matthes ◽  
Frederick E. Spada ◽  
Andrey Ovcharenko ◽  
Bernhard E. Knigge ◽  
Frank E. Talke
Keyword(s):  
Relative Humidity ◽  
Flying Height ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Height Control ◽  
Thermal Flying Height Control

van der Waals force calculation between laminated media, pertinent to the magnetic storage head-disk interface

2005 ◽  
Vol 97 (10) ◽  
pp. 104503 ◽  
Author(s):  
Lee R. White ◽  
Raymond R. Dagastine ◽  
Paul M. Jones ◽  
Yiao-Tee Hsia
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Force ◽  
Magnetic Storage ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Force Calculation

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.

Head-Disk Interface Issues for Near Contact Recording

2001 ◽  
Author(s):  
R. H. Wang ◽  
V. Raman ◽  
U. V. Nayak
Keyword(s):  
Ambient Pressure ◽  
Disk Drive ◽  
Flying Height ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Magnetic Spacing ◽  
Wear And Corrosion ◽  
Disk Lubricant ◽  
Contact Recording

Abstract As the magnetic recording density increases towards hundreds of Gb/in2, both the magnetic spacing and head-disk clearance decrease to < 10 nm. By one estimate, the magnetic spacing for 1 Tb/in2 is about 6 nm and the read width is ∼ 30 nm. There are at least two different approaches to achieving this. The first one is an extension of the traditional flying interface and the second is contact recording. In the former case one needs to be concerned about maintaining adequate clearance both at sea level and at higher elevation whereas in the latter case the wear and corrosion of the heads and disks may pose major challenges. In the flying regime, an accelerated test to assess the relative integrity of the head-disk interface is described here. This is accomplished by monitoring the acoustic emission, capacitance or friction between the head and the disk as the ambient pressure is reduced. The pressure at which an abrupt change in the above signals takes place is called take-off pressure (TOP). This is also known as altitude avalanche measurement. With this method it is possible to compare different disk and head designs at the full velocity of the slider. We present results correlating the TOP with disk roughness and the influence of disk lubricant. An example of how head-disk interference takes place in a disk drive will be given for an experimental 10 nm flying slider. The effects of radial flying height profile, take-off height of the disk, and the disk curvature on mechanical spacing are presented. The results of changes occurring on the air bearing surface and the disks after long term flyability test are discussed.

Head-disk interface considerations at 10-nm flying height

2002 ◽  
Vol 38 (5) ◽  
pp. 2132-2134 ◽  
Author(s):  
Run-Han Wang ◽  
U.V. Nayak
Keyword(s):  
Flying Height ◽  
Head Disk Interface ◽  
Disk Interface
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