Optimization of the SiO2 content in CoPtCr-SiO2 perpendicular recording media for high-density recording

Y. Inaba, T. Shimatsu, T. Oikawa, H. Sato, H. Aoi, H. Muraoka, Y. Nakamura

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54 Citations (Scopus)


Optimization of the SiO2 content for high-density recording was discussed for {(Co90Cr10)80Pt 20}100-z-{SiO2}z perpendicular recording media. The grain size Dgrain decreases significantly from 8.8 to 5.4 nm as the SiO2 content Z increases from 0 to 14.4; however, no significant difference in c-axis orientation was observed. Magnetocrsytalline anisotropy of grains maintains a large value of nearly 8 × 106 erg/cm3, even at 10 at % SiO2 addition, indicating a high potential of perpendicular anisotropy Ku to resist thermal agitation of magnetization. The coercivity Hc increases significantly as the SiO2 increases, which is coincident with the reduction of the slope of magnetization curve α = 4π(dM/dH) due to the enhancement of grain isolation. The Hνcπ shows a maximum at around 11 at % SiO2 (nearly 30 vol % SiO2). A further increase of SiO2 reduces the value of Hc significantly, although the α maintains a constant value of nearly 2, due to thermal agitation of magnetization. The media noise reduces significantly as the SiO2 increases; however, the addition of SiO2 beyond about 13 at % leads to a slight increases in media noise probably due to a significant increase of thermal agitation. The recording resolution D 50 shows a broad maximum of ∼ 420 kFCI at around 11 at % SiO 2, suggesting that the D50 is related to the media noise performance. Experimental results indicate that there is a tradeoff to be made between the thermal stability and media noise performance as a function of SiO2 composition.

Original languageEnglish
Pages (from-to)2486-2488
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number4 II
Publication statusPublished - 2004 Jul
Externally publishedYes


  • CoPtCr-SiO
  • Coercivity
  • Magnetic anisotropy
  • Media noise
  • Perpendicular recording media
  • SiO content
  • Thermal agitation of magnetization

ASJC Scopus subject areas

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


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