M-type ferrite composite as a microwave absorber with wide bandwidth in the GHz range

Sugimoto, Satoshi; Kondo, S.; Okayama, K.; Nakamura, Hajime; Book, D. L.; Kagotani, Toshio; Homma, M.; Ota, H.; Kimura, Masaaki; Sato, Risaburô

doi:10.1109/20.801112

Cited by 175 publications

(63 citation statements)

References 6 publications

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“…In general, the suitable values of RAM can be achieved by adding lossy fillers and/or magnetic particles to a light weight that are physically and chemically stable one and of course have a high ability to absorb electromagnetic wave radiation [7][8][9][10]. The composite approach has been used to improve various material properties, including mechanical, chemical, structural, optical and electrical/magnetic etc [11][12][13][14][15][16][17]. …”

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confidence: 99%

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Sharma

Agarwala

2008

JNanoR

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) were synthesized by a modified flux method that combines the controlled chemical co-precipitation process for nucleation and complete uniform growth during in-situ annealing with NaCl flux under vacuum furnace. Uniform structure morphological transformation of nano crystals from spherical to prism faces were noticed after annealing with increasing temperatures from 200 to 1200 o C for 4 h in vacuum. XRD results showed the single phase nanocrystals of BaFe 18 O 27 with increasing crystallanity and size from 10 to 90 nm during annealing. FESEM and TEM were used to investigate the systematic growth processes of various morphologies of nano crystals. The effect of such systematic morphological transformation of nanocrystals was observed in dielectric, dynamic magnetic and refection loss (RL) properties in Kuband (12.4 -18.0 GHz). A significant increment from -15.23 dB to -43.65 dB with wide range of bandwidth in RL loss is noticed due to the symmetric morphological growth of single phase nano crystals of RAM during annealing. This process of crystal growth, morphology evolution and RL enhancement with respect to increasing temperature were also explained in terms of ostwald ripening and quantum size effect. IntroductionThe electromagnetic interference (EMI) problems have been attracting more attention recently due to the extensive growth in the application of electronic devices such as computer local area networks, mobiles phones, laptops, microwave oven etc [1][2][3]. EMI can cause severe interruption on electronically controlled systems. Furthermore, larger exposure to microwave energy can be potentially harmful to biological systems and human beings. To overcome EMI problems, it is suggested that electromagnetic wave absorbing materials with the capability of absorbing unwanted electromagnetic signals are to be used. For significant absorption of electromagnetic waves, the radar absorption material (RAM) should have electric and/or magnetic dipoles that interact with the electromagnetic fields in the radiation. Microwave absorption materials from magnetic to dielectric related materials used in a high frequency are particularly noticed. But, pure dielectric or magnetic materials are insufficient for absorbing radiation energy. The efficiency of magnetic-dielectric absorbers is high because the complex permittivity (ε΄-jε˝) and permeability (µ΄-jµ˝) differ from zero [4][5][6]. In general, the suitable values of RAM can be achieved by adding lossy fillers and/or magnetic particles to a light weight that are physically and chemically stable one and of course have a high ability to absorb electromagnetic wave radiation [7][8][9][10]. The composite approach has been used to improve various material properties, including mechanical, chemical, structural, optical and electrical/magnetic etc [11][12][13][14][15][16][17].

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confidence: 99%

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Sharma

Agarwala

2008

JNanoR

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“…With increasing demands in microwave communication, microwave dark room, and anti-electromagnetic wave radiation, the hexaferrite has caused great attention [1,2]. Magnetic properties of Ba or Sr ferrite powders strongly depend on the microstructure [3].…”

Section: Introductionmentioning

confidence: 99%

Study of morphological and magnetic properties of microwave sintered barium strontium hexaferrite

Kanagesan

Jesurani

Ramachandran

et al. 2012

J Mater Sci: Mater Electron

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Magnetic materials are important electronic materials that have a wide range of industrial and commercial applications. Barium strontium hexaferrite (Ba 0.5 Sr 0.5 Fe 12 O 19 -BSF) were prepared by a sol-gel method using D-Fructose as fuel and the heat treatment was carried out in a microwave furnace. The effects of the sintering temperature on the morphology, crystalline structure and magnetic properties are studied. Sintering temperature affected the grains in compact samples. The sintered product possessed dense microstructure with clear micro grains and is in consistence with the XRD analysis based on the peak intensity of the (107) plane. Magnetic measurement shows that the barium strontium hexaferrite sample sintered at 1,150°C has the coercive field of 1,998 Gauss, remnant magnetization of 38.87 emu/g and the saturation magnetization of 53.44 emu/g.

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“…Actually ferrite materials have good electromagnetic wave absorption ability in UHF and SHF bands by cationic site substitution and composition controll. 17), 18) In this study, the ferrite powders having large potential for the electromagnetic absorption were prepared by mild chemical wet methods such as precipitation and hydrothermal ones. The electromagnetic wave absorption properties were investigated on the concentration-gradient resin composite including the above powders.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic wave absorption on resin composite including ferrite particles with concentration gradient

Itoh

Machida

2014

J. Ceram. Soc. Japan

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The Fe 3 O 4 particles were prepared from iron chloride by the hydrothermal reaction. The resultant Fe 3 O 4 particles possessed good crystalinity when using the NH 4 OH precipitant and showed the high saturated magnetization value of ca. 90 emu/g. Resin compacts including above ferrite powders were prepared using a centrifugal molding technique. The resultant concentrationgradient resin composites exhibited better broadband electromagnetic wave absorption than the homogeneous resin compacts (no gradation). Such absorption ability is responsible for the suppression of undesirable reflection on the incidence plane and effective thermal loss transducing of electromagnetic wave near the reflector where the magnetic powders are condensed.

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M-type ferrite composite as a microwave absorber with wide bandwidth in the GHz range

Cited by 175 publications

References 6 publications

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Study of morphological and magnetic properties of microwave sintered barium strontium hexaferrite

Electromagnetic wave absorption on resin composite including ferrite particles with concentration gradient

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