Amorphous submicron particle chains with high permeability

Y. Shimada, Y. Endo, M. Yamaguchi, S. Okamoto, O. Kitakami

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Amorphous Fe-P-B particles with submicron sizes were synthesized by chemical precipitation in aqueous solutions. The particles having a spherical shape exhibit good magnetic softness and high saturation magnetization. When they are precipitated in a magnetic field, they are connected to each other to form a chain shape. The high aspect ratio of the chains reduces appreciably the demagnetization field associated with isolated particles, resulting in significant improvement of high permeability performance. In this paper, investigations on the external and internal structures of the chains, uniaxial anisotropy caused by aligning the chains in an external magnetic field, frequency dispersion of permeability, and thermal change of the high permeability feature are presented. Finally, comparison of permeability for particles with various sizes is made with the present chain samples. In addition to the superior high permeability feature compared to other magnetically soft particles, the chains exhibit low loss characteristics at high frequencies up to a few GHz. It is also demonstrated that permeability is improved by annealing at 150°C in vacuum. These results suggest that the particle chains have a high potential for high-frequency applications such as inductor cores and electromagnetic noise absorbers.

Original languageEnglish
Article number6028019
Pages (from-to)2831-2834
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number10
Publication statusPublished - 2011 Oct


  • Amorphous
  • high frequency
  • particle chains
  • permeability
  • submicron particles

ASJC Scopus subject areas

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


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