Thermal stability and nanostructure of CoCrPt longitudinal recording media

Mingjun Yu, Mary F. Doerner, David J. Sellmyer

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


We report a systematic study of activation volumes and their correlation with physical grain sizes and thermal stability in CoCrPt media fabricated by magnetron sputtering. Different underlayers and CoCrPt layer thicknesses were used to provide a range of lateral grain sizes, Mrδ (product of remanence Mr and film thickness δ) values, and remanence coercivities. Two methods, namely the field-sweep-rate dependence of coercivity and measurements of magnetic viscosity and irreversible susceptibility, were used to determine the activation volumes and the results obtained from the two methods are in reasonable agreement. For CoCrPt layer thickness from 10 nm to 27 nm, the activation volumes of these films range from about 3×10-18 cm3 to 5×10-18 cm3, which indicate that these films are thermally stable. Furthermore, for most samples the activation volumes are close to the volumes of the physical CoCrPt grains. This suggests that the magnetic grains in these films switch almost independently. Films with physical grain sizes small enough to approach thermal instability are also discussed.

Original languageEnglish (US)
Pages (from-to)1534-1536
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number4 PART 1
StatePublished - 1998


  • Cocrpt
  • Longitudinal recording media, nanostructure
  • Thermal stability

ASJC Scopus subject areas

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


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