Study of Head-Disk Interface Characterization Using Touchdown Sensor and Electromagnetic Signal in Hard Disk Drives

Yuan Ma (Corresponding Author), Sidney Xue, Jih Ping Peng, David B. Bogy

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


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.

Original languageEnglish
Article number7112145
JournalIEEE Transactions on Magnetics
Issue number11
Publication statusPublished - 1 Nov 2015
Externally publishedYes


  • head media spacing signal
  • Head-disk interface
  • touchdown sensor
  • touchdown stage identification

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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