Slider Overcoats for Enhanced Interface Durability in Magnetic Recording Applications

1995 ◽  
Vol 117 (1) ◽  
pp. 86-93 ◽  
Author(s):  
S. K. Ganapathi ◽  
Timothy A. Riener
Keyword(s):  
Magnetic Recording ◽  
Friction And Wear ◽  
Disk Drive ◽  
Disk Surface ◽  
Electrical Performance ◽  
Head Disk Interface ◽  
Bearing Surface ◽  
Component Level ◽  
Disk Interface ◽  
Significant Performance

The effects on tribological performance of air bearing surface overcoats on magnetic recording sliders are presented. Both component level and disk drive level testing indicate that significant performance enhancements are afforded by the overcoat, and that both stiction/friction and wear of the head/disk interface are reduced, thus increasing interface durability. The degradation in electrical performance of the heads due to the presence of the overcoat is shown to be consistent with that predicted by the Wallace equation. In addition, it is shown that the performance enhancements of the overcoat are achieved only in the presence of lubricant on the disk surface, suggesting that the overcoat lubricant interaction may be more benign than the interaction of the lubricant with the slider material.

Dynamic Analysis of Sliding Contacts at Head-Disk Interface

2002 ◽  
Author(s):  
T.-J. Chuang ◽  
S. M. Hsu
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Time History ◽  
Disk Drive ◽  
Element Model ◽  
Disk Surface ◽  
Magnetic Data ◽  
Head Disk Interface ◽  
Sliding Contacts ◽  
Disk Interface

As magnetic data storage technology moves towards higher areal data density with higher rotational speeds and lower flying heights, the propensity of severe sliding contacts at the head-disk interface is bound to increase. The tribological performance of the head-disk interface will have significant impact on the durability and service life of the hard disk drive (HDD). A 3D finite element model is constructed to simulate the high speed impact event of a slider on the disk surface. For a given design of the disk with known layer thicknesses and properties, as well as that of the slider with its surface texture, the model predicts contact zone, depth force and duration as well as time-history of energy transfer and its partition, substrate stress and plastic zone for a given impact velocity. The effects of the material properties and layer thicknesses on the performance of the HDD are investigated.

Pumping Effect of Slider Air Bearing Surface for Non-Langmuir Adsorption

2010 ◽  
Author(s):  
Bo Zhang ◽  
Akira Nakajima
Keyword(s):  
Disk Surface ◽  
Air Bearing ◽  
Head Disk Interface ◽  
Bearing Surface ◽  
Adsorption Model ◽  
Adsorbed Film ◽  
Disk Interface ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Slider Air Bearing

Numerical analysis of the adsorbed film thickness at the air bearing surface is conducted using the non-Langmuir adsorption model. It is found that the adsorbed film at the air bearing surface becomes significant when the viscosity of adsorbed film is higher than about 1 Pa s. The adsorbed contaminant will accumulate at the rear end of the slider, and it is possible that the accumulated liquid-like contaminant may form a liquid tail which will directly contact with the disk surface, resulting in a crush of the head/disk interface.

Effect of Slider Burnish on Disk Damage During Dynamic Load/Unload

1998 ◽  
Vol 120 (2) ◽  
pp. 332-338 ◽  
Author(s):  
M. Suk ◽  
D. Gillis
Keyword(s):  
Contact Stress ◽  
Disk Surface ◽  
Hertzian Contact ◽  
Radius Of Curvature ◽  
Air Bearing ◽  
Head Disk Interface ◽  
Bearing Surface ◽  
Disk Interface ◽  
Current Design ◽  
Hertzian Contact Stress

Two of the most difficult issues to resolve in current design of head/disk interface in magnetic recording devices are stiction and durability problems. One method of overcoming these problems is by implementing a technology known as load/unload, where the system is designed so that the slider never touches the disk surface. One potential problem with this type of system is slider/disk contact induced disk defects. The objective of this paper is to show that the likelihood of disk scratches caused by head/disk contacts during the load/unload process can be significantly decreased by rounding the edges of the air-bearing surface. Using the resistance method, we observe that head/disk contacts burnish the corners of the slider and thereby decrease exponentially with load/unload cycles. A well burnished slider rarely causes any disk damage thus resulting in an interface with significantly higher reliability. A simple Hertzian contact stress analysis indicates that the contact stress at the head/disk interface can be greatly decreased by increasing the radius of curvature of the air-bearing surface edges.

A Method to Detect Head Media Spacing Change in a Hard Disk Drive Using an Embedded Contact Sensor

2019 ◽  
Author(s):  
Rahul Rai ◽  
Puneet Bhargava ◽  
Bernhard Knigge ◽  
Aravind N. Murthy
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Disk Surface ◽  
Physical Change ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Frequency Components ◽  
Contact Sensor

Abstract Growth in the demand for higher capacity hard disk drives (HDD) has pushed the requirement for head-media spacing (HMS) to sub-nanometer levels. The drop in operational clearance makes a head-disk interface (HDI) more susceptible to potential head-wear and contamination related issues. Such degradation processes are often accompanied by a noticeable shift in the head-disk clearance. Hence monitoring an interface for a spacing change can be helpful in early detection of its imminent failure. In this paper, we present a method to detect the change in head-disk spacing using an embedded contact sensor (ECS). This technique involves the analysis of ECS dynamic response for an interface that is subjected to heater induced spacing modulations. As the head moves closer to the disk surface, the magnitude of the ECS frequency components can be used to determine the ‘characteristic spacing’ which can be used as a metric to detect any physical change for a given interface.

Head–Disk Interface Materials Issues in Heat-Assisted Magnetic Recording

2014 ◽  
Vol 50 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Bruno Marchon ◽  
Xing-Cai Guo ◽  
Bala Krishna Pathem ◽  
Franck Rose ◽  
Qing Dai ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Head Disk Interface ◽  
Heat Assisted Magnetic Recording ◽  
Disk Interface ◽  
Interface Materials

Numerical Investigation of Thermal Effects on a HAMR Head-Disk Interface

2014 ◽  
Author(s):  
Kyaw Sett Myo ◽  
Weidong Zhou ◽  
Xiaoyang Huang ◽  
Shengkai Yu
Keyword(s):  
Temperature Field ◽  
Laser Beam ◽  
Numerical Investigation ◽  
Thermal Effects ◽  
Hard Disk ◽  
Disk Surface ◽  
Recording Media ◽  
Head Disk Interface ◽  
Disk Interface ◽  
High Density Recording

Heat-assisted magnetic recording (HAMR) is one of prospective high density recording technologies in current hard disk industry. It requires heating a spot on the recording media with the laser beam to overcome the superpara-magnetic limit. The heat produced by laser beam causes the temperature field on the hard disk surface to be highly non-uniform, which may lead to unexpectedly severe lubricant loss, or even the failure of the whole HAMR system. In the meantime, the heat loss caused by the optical delivery system may cause unwanted thermal protrusion on the slider body, which may affect slider’s flying stability in the end.

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