Magnetic properties to optimize the Ku2 effect in perpendicular recording media

Hideo Sato, Takehito Shimatsu, Takeshi Kondo, Sadavuki Watanabe, Hajime Aoi, Hiroaki Muraoka, Yoshihisa Nakamura

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We calculated the optimal values of the first- and second-order uniaxial magnetic anisotropy energy terms, Ku1 and Ku2, for thermal stability and writability in perpendicular media which use the Ku2 effect. The magnetic energy barrier ΔE for the remanent state with demagnetizing field 4π〈m s〉was calculated for various Ku1 and Ku2 values, and we obtained the grain volume Vgrain to satisfy ΔEVgrain/kT = 60 for thermal stability (k is the Boltzmann constant, and T the absolute temperature). Moreover, the switching field was calculated assuming a saturation field less than 16 kOe for good writability. The Ku2 term enhances the AE in the remanent state of magnetization, without a notable increase in Hs. It is concluded that the best (Ms) value to take advantage of the Ku2 effect is about 500 emu/cm3, with Ku 1= 5 x 106 erg/cm3 and Ku 2= 2.6 x 106 erg/cm3. The Ku2 term allows Vgrain (and also the grain size) to be reduced by almost one-half, compared with a grain without a Ku 2term, while simultaneously achieving good thermal stability and writability.

Original languageEnglish
Pages (from-to)2387-2389
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number10
Publication statusPublished - 2006 Oct


  • Energy barrier
  • anisotropy energy term
  • grain volume
  • perpendicular recording media
  • saturation field
  • second-order uniaxial magnetic
  • thermal stability

ASJC Scopus subject areas

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


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