Switching field distribution of CoPtCr-SiO2perpendicular recording media obtained by subtracting thermal agitation of magnetization

T. Shimatsu, T. Kondo, K. Mitsuzuka, S. Watanabe, H. Aoi, H. Muraoka, Y. Nakamura

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The effect of thermal agitations on the switching field distribution (SFD) of CoPtCr-Si02 perpendicular media was investigated, and the “intrinsic” SFD caused by variations in the grain-to-grain switching field was determined. DC demagnetizing (DCD) magnetization curves and minor DCD (M-DCD) magnetization curves were measured at applied field-sweep rates of ~ 10 Oe/s and ~ 108 Oe/s. We estimated the SFD from the difference between the DCD and M-DCD curves, and defined them as ΔHr/Hr (at ~ 10 Oe/s) and Δ Hpr /Hrp (at ~ 108 Oe/s). The values of Δ Hr/Hr were much larger than those of ΔHrp/Hrp. Moreover, Δ Hr/Hr increased faster than ΔHrp /Hrp as the thickness decreased, suggesting that the SFD measured at vibrating sample magnetometer (VSM) time scales is significantly influenced by thermal agitation. The intrinsic SFD estimated using a series of media with various film thicknesses was about 0.14, which was 55%-75% of ΔHr/Hr for 8-16-nm-thick media. An analysis of the temperature dependence of ΔHr/Hr supported this conclusion. It is concluded that the SFD measured at VSM time scales is significantly influenced by thermal agitation of the magnetization, and the intrinsic SFD is likely to be nearly half that measured at VSM time scales.

Original languageEnglish
Pages (from-to)2384-2386
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number10
Publication statusPublished - 2006 Oct


  • Film thickness
  • agitation of magnetization
  • perpendicular recording media
  • pulse field
  • switching field distribution (SFD)
  • temperature
  • thermal

ASJC Scopus subject areas

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


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