Improvement of magnetic intergranular isolation and evaluation of read/write characteristics on SmCo5 perpendicular magnetic thin films

Toru Asahi, Isao Koizumi, Yuko Egawa, Masahiro Yoshino, Atsushi Sugiyama, Jiro Hokkyo, Takanori Kiya, Jun Ariake, Kazuhiro Ouchi, Tetsuya Osaka*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


SmCo5 alloy is a promising candidate for ultra-high-density perpendicular magnetic recording (PMR) media because of its high uniaxial magnetocrystalline anisotropy Ku of more than 1.1×10 8 erg/cm3. Previously, we successfully achieved high Ku in a sputter-deposited SmCo5 thin film by introducing a Cu/Ti dual underlayer. However, in order to apply the SmCo5 films to practical PMR media, it is necessary to decrease medium noise. A granulated magnetic film comprising of small and magnetically decoupled grains is effective in reducing the medium noise. In this paper, we have proposed a new granular film that is fabricated by partial thermodiffusion of Cu between the SmCo continuous layer and the Cu underlayer, which is granulated using compositional segregation caused by the addition of Ta2O5. We have analyzed the magnetic properties, magnetic domain size, and magnetization reversal process of the proposed SmCo5 film. The magnetic domain size decreased and the magnetization reversal process changed from the magnetic-wall-motion mode to a coherent rotation mode to some extent on isolation of magnetic grains. The read/write characteristics of granulated SmCo5 double-layered media were also evaluated. The medium noise decreased and the signal-to-noise ratio increased for the granulated double-layered (PMR) medium.

Original languageEnglish
Pages (from-to)3784-3788
Number of pages5
JournalJournal of Magnetism and Magnetic Materials
Issue number23
Publication statusPublished - 2010 Dec


  • High Ku material
  • Perpendicular magnetic recording
  • Read/Write (R/W) characteristics
  • SmCo thin film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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