Enhancement of microwave absorption characteristics in aligned M-type barium ferrite Ba1-xLaxZnxFe12-x-y(Me0.5 Mn0.5)yO19 (x = 0.0-0.5, Me: Sn, Zr, y = 1.0-3.0) by metal substitution

Toshio Kagotani, Daisuke Fujiwara, Satoshi Sugimoto, Koichiro Inomata, Motofumi Homma

Research output: Contribution to journalArticle

Abstract

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(Me0.5 Mn0.5)yO19 compound. The c-axis aligned samples were formed into toroidal shapes. The magnetic properties (MS, HA) and the resonance absorption properties (μ′r, μ″r 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 samples3). 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 1.02 mm. It is therefore concluded that Sn or Zr substitution is effective in enhancing the electromagnetic wave absorption characteristics of M-type Ba ferrite absorber.

Original languageEnglish
Pages (from-to)58-62
Number of pages5
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Volume50
Issue number1
DOIs
Publication statusPublished - 2003 Jan

Keywords

  • Complex permeability
  • EMC
  • Electromagnetic absorper
  • M-type Ba ferrite
  • Magnetic resonance

ASJC Scopus subject areas

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry

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