Servo-pattern and guard-band formation in perpendicular discrete-track media by ion irradiation

Junichi Yasumori*, Yoshiaki Sonobe, Simon J. Greaves, Hiroaki Muraoka

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


An embedded servo pattern was fabricated using the ion irradiation method. The servo pattern was analyzed using a spinstand with a flyable read/write head and compared with a conventional medium written by a dedicated servo writer. The embedded servo patterns were clearly detected. The good quality of the servo signal proved the effectiveness of the ion irradiation process. No domain wall noise was observed in the ion-irradiated servo area, indicating the absence of large maze domains. LLG simulations were used to investigate the behavior of written tracks and soft-guard-bands of DTM fabricated by ion irradiation. A conventional continuous medium showed an expansion in the width of written tracks as the continuous layer thickness increased. In DTM, track expansion was prevented by the grooves. According to the simulation results, similar magnetic track widths can be obtained in media with soft-guard-bands as in conventional DTM media with air grooves. The Ku reduction in the grooves should align the magnetization of the irradiated guard band region in-plane to realize a successfully erased guard band.

Original languageEnglish
Article number5257168
Pages (from-to)3703-3706
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number10
Publication statusPublished - 2009 Oct
Externally publishedYes


  • Discrete-track media
  • Ion irradiation
  • Magnetic modification
  • Patterned media

ASJC Scopus subject areas

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


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