Study of the head disk interface using touchdown sensors and electro-magnetic signals in hard disk drives

Y. Ma, S. Xue, J. Peng, D. Hellman, D. B. Bogy

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review


The current trend of increasing the areal density in hard disk drives (HDDs) required the fly height of the air bearing slider to decrease from tens of nanometers to only a few nanometers. With the thermal fly-height control (TFC) slider, the fly height can vary from nominal fly height to contact. Controlling the fly height of the slider can also provide insight into the characteristics of the HDI. In drive-level testing, however, the means to evaluate the HDI has been limited to head-media spacing (HMS) signals and servo control signals. With the recently introduced touchdown sensor (TDS, also known as embedded contact sensor), HDI properties can be determined by comparing TDS signal and HMS signal. The TDS has been proven able to identify different HDI characteristics including asperity, pit, lube moguls and surface microwaviness in component level [1]. However, there have been limited reports regarding the relationship between TDS and HMS. In this paper, a correlation between TDS and HMS is established and discussed and the patterns of TDS and HMS are then used to identify different stages of TD.

Original languageEnglish
Title of host publication2015 IEEE International Magnetics Conference, INTERMAG 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781479973224
Publication statusPublished - 14 Jul 2015
Externally publishedYes
Event2015 IEEE International Magnetics Conference, INTERMAG 2015 - Beijing, China
Duration: 11 May 201515 May 2015

Publication series

Name2015 IEEE International Magnetics Conference, INTERMAG 2015


Conference2015 IEEE International Magnetics Conference, INTERMAG 2015

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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