The microwave absorbing and resonance phenomena of Y-type hexagonal ferrite microwave absorbers

Kwon, Hyu‐Sang; Shin, Jeong-Hun; Oh, Jeong-Hoon

doi:10.1063/1.355476

Cited by 201 publications

(79 citation statements)

References 5 publications

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“…23,131,132,133,134,135,136 High permeability is attributed to spin rotation and domain-wall motions. The c-plane -substituted W-hexaferrites with sufficiently high cobalt content are magnetically planar.…”

Section: Hexaferritesmentioning

confidence: 99%

Microwave ferrites, part 1: fundamental properties

Özgür

Alivov

Morkoç̌

2009

J Mater Sci: Mater Electron

318

110

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Ferrimagnets having low RF loss are used in passive microwave components such as isolators, circulators, phase shifters, and miniature antennas operating in a wide range of frequencies (1-100 GHz) and as magnetic recording media owing to their novel physical properties. Frequency tuning of these components has so far been obtained by external magnetic fields provided by a permanent magnet or by passing current through coils. However, for high frequency operation the permanent part of magnetic bias should be as high as possible, which requires large permanent magnets resulting in relatively large size and high cost microwave passive components. A promising approach to circumvent this problem is to use hexaferrites, such as BaFe 12 O 19 and SrFe 12 O 19 , which have high effective internal magnetic anisotropy that also contributes to the permanent bias.Such a self-biased material remains magnetized even after removing the external applied magnetic field, and thus, may not even require an external permanent i

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Section: Hexaferritesmentioning

confidence: 99%

Microwave ferrites, part 1: fundamental properties

Özgür

Alivov

Morkoç̌

2009

J Mater Sci: Mater Electron

318

110

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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]. …”

mentioning

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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“…The microwave measurements were based on the transmission/reflection method (T/R) using a rectangular waveguide as the confining medium for the samples [6][7][8][9][10] . A network analyzer was used to measure the magnitude and phase response of the samples under test (SUT) by the comparison with the signal transmitted by the SUT and that reflected from its input.…”

Section: Methodsmentioning

confidence: 99%

Microwave absorption properties of Co, Cu, Zn: substituted hexaferrite polychloroprene nanocomposites

et al. 2008

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The magnetic behavior and its relationship with microwave absorbing properties have been investigated for doped Z-type barium hexaferrites ( , and Zn 2+ ions make possible the use of these materials as RAMs, due to the frequency dependence of μ r * (permeability), responsible for the location of the hexaferrite natural resonance.The Cu 2+ ions distort the crystalline field due to their electronic configuration, and this behavior results in an increase in the saturation magnetization (M s ), which improve the magnetic permeability. Similarly, the superparamagnetic contribution (associated to the nanometric size) led to the improvement of the microwave absorption.

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The microwave absorbing and resonance phenomena of Y-type hexagonal ferrite microwave absorbers

Cited by 201 publications

References 5 publications

Microwave ferrites, part 1: fundamental properties

Microwave ferrites, part 1: fundamental properties

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Microwave absorption properties of Co, Cu, Zn: substituted hexaferrite polychloroprene nanocomposites

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