Influence of patterning fluctuation on read/write characteristics in discrete track and bit patterned media

Mitsuhiro Hashimoto, Kenji Miura, Hiroaki Muraoka, Hajime Aoi, Roger Wood, Michael Salo, Yoshihiro Ikeda

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The read/write characteristics of non-patterned media (NPM), discrete track media (DTM), and bit patterned media (BPM) are examined by modeling the magnetization distribution of NPM and patterning fluctuation of DTM. By comparing spin-stand measurement with calculation, the magnetization distribution of NPM was well characterized with a new Voronoi cell magnetic cluster model, in which the cluster size at the track edge, 〈Dedge〉, was larger than that at the track center, 〈Dcenter〉 by a factor of two. Based on an analysis of patterning fluctuations seen in SEM images of DTM, line-edge roughness (LER) was modeled as a long-wavelength center-line roughness (CLR) plus a short-wavelength line-width roughness (LWR). It was confirmed that the standard deviation of the patterning fluctuation was much smaller than that of the magnetic fluctuation for NPM. This allowed DTM to achieve higher off-track performance than NPM. By examining the 747 curves, it was revealed that DTM could have an advantage in track-density of up to approximately 25% assuming patterning fluctuations can be well controlled at high track density. In BPM, fabricating accurate dots is essential. The relationship between dot defect rate and patterning fluctuation was examined, and the maximum allowable standard deviation of LER was derived as 2 nm for achieving 1 Tbspi.

Original languageEnglish
Pages (from-to)2935-2943
Number of pages9
JournalJournal of Magnetism and Magnetic Materials
Issue number22
Publication statusPublished - 2008 Nov
Externally publishedYes


  • Magnetic fluctuation
  • Media noise
  • Patterning fluctuation
  • Perpendicular magnetic recording

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


Dive into the research topics of 'Influence of patterning fluctuation on read/write characteristics in discrete track and bit patterned media'. Together they form a unique fingerprint.

Cite this