Recording resolution and writability for (Co-Pt)-SiO2/Co- SiO2 hard/soft-stacked granular perpendicular media

T. Shimatsu, Y. Inaba, S. Watanabe, O. Kitakami, S. Okamoto, H. Aoi, H. Muraoka, Y. Nakamura

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11 Citations (Scopus)


The magnetic properties and recording performance of hard/soft stacked media consisting of a magnetically hard 9-nm-thick (CoPt)-SiO2 layer underneath a thin (2-3 nm) soft granular layer were studied. Experimental results indicated that an increase in the mean value of saturation magnetization of the soft layer 〈Mssoft〉 was very effective at improving the recording resolution D50 due to an increase in the slope of magnetization curve a. The use of a Co-SiO2 layer, which has the highest 〈Mssoft〉 in the present study, resulted in the highest D50 value. It is likely that the increase in α was mainly caused by the demagnetization field in grains due to the difference between 〈Mssoft〉 and the mean value of saturation magnetization of the hard layer, 〈Ms hard〉. Moreover, it was successfully demonstrated that the magnetization reversal of (Co-Pt)-SiO2/Co-SiO2 stacked media changed systematically as theoretically predicted on reducing the interfacial exchange coupling by using NiFeCr-SiO2 or Pt-SiO 2 interlayers. The reduction of remanence coercivity Hr was achieved by controlling the thickness and film composition of the interlayer, moreover, a high- lang;Mssoft〉 enhanced the Hr reduction. The Hr reduction improved recording writability without degrading D50, the signal to medium noise ratio SNmR and thermal stability.

Original languageEnglish
Pages (from-to)2103-2105
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number6
Publication statusPublished - 2007 Jun 1


  • Hard/soft stacked media
  • Interfacial exchange coupling
  • Large saturation magnetization
  • Perpendicular recording media
  • Recording resolution
  • Recording writability
  • Remanence coercivity
  • Signal to medium noise ratio

ASJC Scopus subject areas

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

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