High permeability and low core losses of nanocrystalline Fe-Nb-Zr-B-Cu alloys

A. Makino, T. Hatanai, S. Yoshida, N. Hasegawa, A. Inoue, T. Masumoto

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Nanocrystalline Fe-M-B (M=Zr or Nb) alloys prepared by crystallization of rapidly quenched amorphous ribbons are known as a new class of soft magnets with high saturation magnetization. In order to improve their soft magnetic properties further, the reduction of their magnetostriction to zero was attempted by a combined addition of Zr and Nb, because the signs of the magnetostriction of the Fe-Zr-B and the Fe-Nb-B at each optimum condition are known to be opposite. Further, the B concentration was reinvestigated under a Cu addition and the combined addition of Zr and Nb in order to further refine the grain size and to improve the intergranular exchange coupling. As a result, the small average grain size of 8nm and nearly zero magnetostriction has been simultaneously obtained in the Fe84Nb3.5Zr3.5B8Cu1 alloy. This alloy simultaneously exhibits the high permeability of 100,000 (at 1kHz) and the high saturation flux density of 1.53T, satisfying the both properties in the highest level among the rapidly quenched ribbons ever reported. The core losses of the nanocrystalline Fe84Nb3.5Zr3.5B8Cu1 alloy are lower than those of the amorphous Fe-Si-B alloys over a wide frequency and Bm (maximum induction) range. Further, the core losses are almost unchanged under the stresses such as epoxy resin molding. These new nanocrystalline materials are suitable for use in advanced electronic devices such as inductors or transformers.

Original languageEnglish
Pages (from-to)121-125
Number of pages5
JournalScience Reports of the Rerearch Institutes Tohoku University Series A-Physics
Issue number1
Publication statusPublished - 1996 Mar
Externally publishedYes


  • Amorphous alloy
  • Core loss
  • Crystallization
  • Melt spun ribbon
  • Nanocrystalline
  • Soft magnetic alloy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Metals and Alloys


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