Compositional Effect on Soft Magnetic Properties of Co-Fe-Si-B Amorphous Alloys with Zero Magnetostriction

Akihiro Makino, Akihisa Inoue, Tsuyoshi Masumoto

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4 Citations (Scopus)


The compositional effect on magnetic properties of Co-Fe-Si-B amorphous alloys was examined with the aim of finding an optimum composition for a magnetic head material. The lowest coercivity (Hc) and the highest permeability at 0.3 kHz (μ0.3) in the as-quenched state were obtained at 0.94Co/(Co + Fe) and in the metalloid range of 24 to 25%(Si + B) and 0.6Si/(Si + B). The composition range is in agreement with that in which the highest glass-forming capacity is obtained and hence the good soft magnetic properties in the limited composition range are presumably due to a high degree of amorphicity and structural homogeneity. The permeability at 100 kHz (μ100) shows a maximum value in the range of 27%(Si + B) and 0.65 to 0.70Si/(Si + B) and the difference of the optimum compositions between μ0.3 and μ100 is due to the necessity of high electrical resistivity for μ100. The annealing results in the change of the optimum composition to 0.6Si/(Si + B) for μ100 and 0.5Si/(Si + B) for Hc. The annealing-induced change is interpreted from the difference in the compositional effect on the homogeneity and thermal stability of the amorphous structure. Thus, the combination of high magnetization values of 98×l0-6 to 113 × 10-6 and high permeability at 0.3 kHz reaching 19.21 × 104 in the annealed state is achieved at 0.6Si/(Si + B) where the amorphous structure has high thermal stability and hence the metalloid composition is concluded to be optimum for an amorphous magnetic head material.

Original languageEnglish
Pages (from-to)884-890
Number of pages7
JournalMaterials Transactions, JIM
Issue number10
Publication statusPublished - 1990
Externally publishedYes


  • amorphous ribbon
  • cobalt-iron-silicon-boron system
  • coercivity
  • compositional effect
  • permeability
  • saturation magnetization
  • soft magnetic property
  • zero magnetostriction

ASJC Scopus subject areas

  • Engineering(all)


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