Title :
Study of Head-Disk Interface Characterization Using Touchdown Sensor and Electromagnetic Signal in Hard Disk Drives
Author :
Yuan Ma ; Xue, Sidney ; Jih-Ping Peng ; Bogy, David B.
Author_Institution :
Dept. of Mech. Eng., Univ. of California at Berkeley, Berkeley, CA, USA
Abstract :
With the introduction of thermal fly-height control sliders, the local head-disk clearance can be reduced to a range from ~10 nm to contact. This actively controlled touchdown (TD) has been used as a way to study the head-disk interface (HDI), the characteristics of which greatly affect the areal density and reliability of drives. In this paper, a high spatial resolution TD study is performed at the drive level using TD sensor signals and head-media spacing signals. Different flying stages, including passive flying, TD transition, and over push modulation, are identified from the experimental results. A correlation between the aforementioned signals at the passive flying stage is found to represent the disk surface property. The passive flying stage and over push modulation stage of TD are further analyzed in both the time and frequency domains. By establishing a correlation between the fly height and the temperature response, we can provide insight into the heat transfer model for the HDI.
Keywords :
disc drives; frequency-domain analysis; hard discs; tactile sensors; time-domain analysis; actively controlled touchdown; disk surface property; drive level; electromagnetic signal; frequency domain; hard disk drives; head-disk interface characterization; head-media spacing signals; heat transfer; local head-disk clearance; over push modulation; passive flying stage; spatial resolution; temperature response; thermal fly-height control sliders; time domain; touchdown sensor; Correlation; Frequency modulation; Frequency-domain analysis; Magnetic heads; Surface waves; Head???disk interface (HDI); head media spacing signal; head-disk interface; head-media spacing (HMS) signal; touchdown sensor; touchdown sensor (TDS); touchdown stage identification;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2015.2434371