Proposal of Granular-Type Cap Layer with High-Ku CoPt Grains and Ferromagnetic Oxide Grain Boundaries for Full Granular Media

Kim Kong Tham, Ryosuke Kushibiki, Tomonari Kamada, Shin Saito

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1 Citation (Scopus)


Investigation of magnetic properties and microstructure for the stacked media with Co80Pt20-30 vol% rare earth (RE) oxide (RE oxide: Gd2O3, Nd2O3, and Sm2O3) cap layers (CLs) deposited on a Co80Pt20-30 vol% B2O3 granular recording layer (GRL) was conducted. It was found that the employment of a granular-type CL with ferromagnetic oxide is effective to control intergranular exchange coupling of the magnetic grains in CoPt-B2O3 GRL while maintaining the granular structure of the CL. In this full granular media, continuous structure of columnar magnetic grains and grain boundaries from the GRL up to the CL can be observed. When a typical ferromagnetic oxide CL, such as CoPt-Gd2O3 (9 nm), is deposited on CoPt-B2O3 GRL (16 nm), the nucleation field is increased from 0.7 to 1.1 kOe, and the saturation field is reduced from 21.5 to 16 kOe which suggest that CoPt-RE oxide is promising for a CL.

Original languageEnglish
Article number8640849
JournalIEEE Transactions on Magnetics
Issue number7
Publication statusPublished - 2019 Jul


  • CoPt-BO
  • ferromagnetic oxide
  • full granular media
  • granular cap layer (CL)
  • high K
  • rare earth (RE) oxide

ASJC Scopus subject areas

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


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