Synthesis of Co100-xPtx alloy fine particles with high coercivity

Takahiro Ibusuki, Tomoaki Sakurai, Osamu Kitakami, Yutaka Shimada

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


In the present study, we have prepared and investigated Co100-xPtx (0 ≤ x ≤ 40) fine particles with the average diameter of D = 3 ∼ 40nm. At a fixed D ∼ 10 nm, the room temperature coercivity Hc increases with the Pt content x and takes a maximum value of 1000 Oe at x ∼ 25 at.% for 3D random assemblies of the particles. Such remarkable enhancement of the coercivity due to Pt is attributed to very strong magnetic anisotropy, as evaluated by the law of approach to saturation. At x ∼ 25 at.%, Hc increases with D due to suppression of thermal agitation and takes a maximum of 4000 Oe around at D ∼ 15 nm. Micromagnetic calculations taking into account dipolar interactions between particles have verified that the magnetic behaviours of Co75Pt25 fine particles can be explained by the coherent rotation model.

Original languageEnglish
Pages (from-to)1295-1298
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number4
Publication statusPublished - 2001 Jul
Externally publishedYes


  • Co-Pt
  • Coercivity
  • Dipolar interaction
  • Fine particle
  • Magnetic anisotropy

ASJC Scopus subject areas

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


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