Enhancement of Microwave Absorption Characteristics in Aligned M-type Barium Ferrite Ba1-xLaxZnxFe12-x-y(Me0.5Mn0.5)yO19 (x=0.0-0.5, Me: Sn,Zr, y=1.0-3.0) by Metal Substitution
| Autor: | Koichiro Inomata, Daisuke Fujiwara, Toshio Kagotani, Satoshi Sugimoto, Motofumi Homma |
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| Rok vydání: | 2003 |
| Předmět: |
Materials science
Mechanical Engineering Metals and Alloys Analytical chemistry Molar absorptivity Electromagnetic radiation Industrial and Manufacturing Engineering Ion Metal chemistry.chemical_compound chemistry visual_art Materials Chemistry visual_art.visual_art_medium Ferrite (magnet) Anisotropy Barium ferrite Microwave |
| Zdroj: | Journal of the Japan Society of Powder and Powder Metallurgy. 50:58-62 |
| ISSN: | 1880-9014 0532-8799 |
| Popis: | Microwave radiation in the GHz band is increasingly being used in many various communication devices. However, this has brought about the problems of electromagnetic interference (EMI). Now M-type Ba ferrite is expected to be used as a powerful countermeasure to EMI. Our recent works have shown that M-type Ba ferrite is promising material for microwave absorber in the GHz range. The electromagnetic resonance absorption properties depend on the complex permeability μ=μ'-jμ", particularly the imaginary part μ"=Ms/2HAα(Ms: saturation magnetization, HA: anisotropy field, a: extinction coefficient). We investigated the effects of substitution composition (x) of Me for Ba (Me: La) and substitution composition (y) of Me ion (Me: Zn, Zr, Sn) for Fe3+ on the electromagnetic absorption properties of the Ba1-xLaxZnxFe12-x-y(Me0.5Mn0.5)yO19 compound. The c-axis aligned samples were formed into toroidal shapes. The magnetic properties (Ms, HA) and the resonance absorption properties (μr', μr" etc) were measured using a VSM and a network analyzer. The aligned Zr-substituted samples (x=0.0, y=1.4) showed values of HA =0.21 MAm-1, and μ'= 7.5 and μ" =7.1 that were higher than those of (TiMn) substituted samples. The matching thickness dm decreased to 0.8 mm at the matching frequency of 7.6 GHz. In the sample of x=0.0 and y=1.5, μ'=7.7 and μ" = 6.7 were obtained, and the matching thickness dm was 0.98 mm at 5.95 GHz. Also, Sn-substituted samples showed high m' and m" values of 6.3 and 6.3, respectively, and dm of 1.02mm. It is therefore concluded that Sn or Zr substitution is effective in enhancing the electromagnetic wave absorption characteristics of M-type Ba ferrite absorber. |
| Databáze: | OpenAIRE |
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