Effect of Substitutional Elements on the Natural Resonance Frequency of Barium M-Type Ferrite

概要

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The effect of substitutional elements (Ti,Sc,Zr,Ti_<0.5>M_<0.5>, Zr_<0.5>M_<0.5>, Sn_<0.5>M_<0.5> (where M=Co,Ni,Zn,Mn,Mg,Cu)) on the natural resonance frequency of Barium M-type hexagonal ferrite (BaFe_<12>O_<19>) was investigated, with the aim of finding a material suitable for use as a microwave absorber in the GHz range. It was found that the anisotropy field (H_A) decreases with increasing amounts of substitutional element, which leads to the natural resonance frequency (fr) and the matching frequency (fm) shifting to lower values. Some Ti_<0.5>M_<0.5> substituted samples exhibited values of fr within the 1 to 20 GHz range, and the minimum reflection loss (R.L.) for these samples was found to be less than -20dB. In particular, because of their large values of magnetic loss ((μ")=4.6 and μ"=4.0), the BaFe_9(Ti_<0.5>Mn_<0.5>)_3O_<19> and BaFe_<9.5>(Ti_<0.5>Mn_<0.5>)_<2.5>O_<19> samples had small matching thicknesses (dm) of 0.58mm and 0.53mm, with matching frequencies (fm) of 12.35GHz and 15.75GHz, respectively. Therefore, it may be concluded that Barium M-type ferrite is a candidate for use as a microwave absorber in the GHz range.
社団法人日本磁気学会の論文
1999-01-20