scholarly journals Magnetic and Microwave Properties of Polycrystalline Gadolinium Iron Garnet

2017 ◽  
Vol 268 ◽  
pp. 287-291 ◽  
Author(s):  
Farah Nabilah Shafiee ◽  
Raba’ah Syahidah Azis ◽  
Ismayadi Ismail ◽  
Rodziah Nazlan ◽  
Idza Riati Ibrahim ◽  
...  
Keyword(s):  
Magnetic Loss ◽  
Ambient Air ◽  
High Energy ◽  
Microwave Properties ◽  
Complex Permeability ◽  
Frequency Range ◽  
Mixed Powder ◽  
Band Frequency ◽  
Suitable Material ◽  
Microwave Loss

The microwave loss in nanosized GdIG particles synthesized using mechanical alloying technique was investigated. There were very few of research on the microwave properties of nanosized particle GdIG and there is no attempt investigating on the material at C-band frequency range and its correlation with the microstructure. Gadolinium (III) iron oxide and iron (III) oxide, α-Fe2O3 were used as the starting materials. The mixed powder was then milled in a high-energy ball mixer/mill SPEX8000D for 3 hours. The samples were sintered at temperature 1200°C for 10 hours in an ambient air environment. The phase formation of the sintered samples was analyzed using a Philips X’Pert Diffractometer with Cu-Kα radiation. Complex permeability constitutes of real permeability and magnetic loss factor were measured using an Agilent HP4291A Impedance Material Analyzer in the frequency range from 10 MHz to 1 GHz. A PNA-N5227 Vector Network Analyzer (VNA) was used to obtain the information on ferromagnetic linewidth broadening, ΔH that represents the microwave loss in the samples in in frequency range of 4 to 8 GHz (C-band). The ΔH value was calculated from the transmission (S21) data acquired from VNA. The single phase GdIG showed low initial permeability and low magnetic loss when applied with low-frequency range energy. From these data, it is validated that GdIG is a suitable material for microwave devices for the high-frequency range.

scholarly journals Effect of Variation Sintering Temperature on Magnetic Permeability and Grain Sizes of Y3Fe5O12 via Mechanical Alloying Technique

2016 ◽  
Vol 846 ◽  
pp. 395-402 ◽  
Author(s):  
Nuraine Mariana Mohd Shahrani ◽  
Raba’ah Syahidah Azis ◽  
Mansor Hashim ◽  
Hassan Jumiah ◽  
Zakaria Azmi ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Magnetic Particles ◽  
Magnetic Loss ◽  
Waste Product ◽  
High Energy ◽  
Complex Permeability ◽  
X Ray Diffraction ◽  
Mixed Powder ◽  
Temperature Separation ◽  
Iron Garnet

This work will focus on the preparation of yttrium iron garnet (Y3Fe5O12, YIG) via mechanical alloying technique derive by steel waste product. The Fe2O3 powder derived from the steel waste purified by using magnetic and non-magnetic particles (MNM) and Curie temperature separation (CTS) technique. The purified powder was then oxidized in air at 500 °C for 9 hours in air. The Fe2O3 was mixed with Y2O3 using high energy ball milling for 9 hours. The mixed powder obtained was pressed and sintered at different temperature 500/600/700/800/900/1000/1100 °C. X-ray diffraction (XRD) shows the YIG is completely form at 1100 °C. The field emission scanning electron microscopy (FESEM) images shows the grain size increases as increase the sintering temperatures. The frequency dependence on the complex permeability, µ’ and magnetic loss, µ’’ in the frequency range 10 MHz to 1 GHz were measured in this study. The results showed that the highest μ΄ is 5.890 obtained from 1100 °C.

Structure, Magnetic and Microwave Properties of Granular Fex(SiO2)1-x Alloys Obtained by Mechanochemical Synthesis

2012 ◽  
Vol 190 ◽  
pp. 585-588
Author(s):  
S.F. Lomayeva ◽  
A.N. Maratkanova ◽  
Konstantin N. Rozanov ◽  
D. A. Petrov ◽  
Eugene P. Yelsukov
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Domain Walls ◽  
Magnetic Loss ◽  
Structural Phase ◽  
High Energy ◽  
Microwave Properties ◽  
Particle Size Reduction ◽  
Milling Medium ◽  
Energy Ball

The structural-phase composition, magnetic and microwave properties of Fex(SiO2)1-x (x=30, 70, 90, 95) nanocomposites have been studied. The composites are produced by high-energy ball milling with either Ar or acetone as a milling medium and milling time of 1 to 64 h. The microwave magnetic properties of the composite in the frequency range of 0.1 to 6 GHz are shown to depend slightly on the phase composition and be governed mainly by the particle size. Reduction of the particle size to about 1 μm results in elimination of magnetic loss at frequencies below 1 GHz, which is attributed to the domain walls motion.

SiC Micro-Threads Prepared within the Carbon Fiber Felt

2008 ◽  
Vol 368-372 ◽  
pp. 843-845
Author(s):  
Feng Yuan ◽  
Hong Jie Wang ◽  
Zhi Hao Jin
Keyword(s):  
Carbon Fiber ◽  
Three Dimensional ◽  
Nitrogen Pressure ◽  
Complex Permeability ◽  
Similar Form ◽  
Frequency Range ◽  
Band Frequency ◽  
X Band ◽  
Carbon Fiber Felt ◽  
Low Nitrogen

Polyacrylonitrile (PAN) based carbon fiber felt which contains abundant various SiC microthreads and some other microstructures was prepared through sintering the pretreated felt at high temperature at low nitrogen pressure. XRD, SEM, TEM, HRTEM analyses for the sintered felt were carried out to study its components and microstructures. There are SiC nanothreads, SiC submicron threads, SiC micron threads and a few SiO2 two- or three-dimensional microstructures (possibly intermix with the similar form of SiC) existed within the inner hollow spaces of the felt. The complex permittivity, complex permeability of the sample in the X-band frequency range were obtained.

Preparation and Electromagnetic Properties of CIP/SiO2/PANI Composites

2013 ◽  
Vol 834-836 ◽  
pp. 187-190
Author(s):  
Ming Ming Wang ◽  
Zhong Lun Zhang ◽  
Wan Jun Hao ◽  
Guo Yan Hou ◽  
Zhi Jun Xin ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
In Situ Polymerization ◽  
Magnetic Loss ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Core Shell ◽  
Network Analyzer ◽  
Frequency Range ◽  
Xrd Patterns

CIP particles first were coated with SiO2 shell by the Stober process , then grafted the polyaniline by in-situ polymerization to prepare CIP/SiO2/PANI core-shell composites. The CIP/SiO2/PANI composites are composed the dielectric loss properties with the the magnetic loss properties, the morphologystructure and electromagnetic properties are characterized by SEMXRD and vector network analyzer, respectively. It is observed that SiO2 and PANI are on the surface of CIP particles, XRD patterns further confirm that the CIP/SiO2/PANI composites are synthesized successfully, and that interaction between components exist in the polymerization. In comparison with CIP, the complex permittivity of CIP/SiO2/PANI composites have certain enhancement in 2-18GHz frequency range, but it has a very small impact on the complex permeability.

Effect of Microwires Diameters on the Microwave Properties of Glass-Coated Microwires/Dielectric Composite

2013 ◽  
Vol 873 ◽  
pp. 366-372
Author(s):  
Yong Jiang Di ◽  
Deng Ming Chen ◽  
Peng Jun Cao ◽  
Bi Jia
Keyword(s):  
Coaxial Line ◽  
Microwave Properties ◽  
Complex Permeability ◽  
Frequency Range ◽  
Dielectric Composite ◽  
Natural Resonance ◽  
Microwave Permeability ◽  
Natural Resonance Frequency ◽  
Microwave Permittivity ◽  
Composite Samples

The microwave properties of Glass-coated FeCuNbVSiB and CoFeNiSiB microwires/dielectric composite with different microwires diameters were studied. Relative complex permeability and complex permittivity was measured by transmission/reflection (T/R) coaxial line method at the frequency range of 2-18 GHz for composite samples. The results show that the microwave permeability and permittivity increases with the lengthening of the microwires in composite. The microwave permeability, natural resonance frequency and microwave permittivity increase with the decrease of the diameter of the microwires.

scholarly journals Enhancement of Complex Permittivity and Attenuation Properties of Recycled Hematite (α-Fe2O3) Using Nanoparticles Prepared via Ball Milling Technique

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1696 ◽  
Author(s):  
Ebenezer Ekow Mensah ◽  
Zulkifly Abbas ◽  
Raba’ah Syahidah Azis ◽  
Ahmad Mamoun Khamis
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Complex Permittivity ◽  
High Energy ◽  
Complex Permeability ◽  
Band Frequency ◽  
Transmission Coefficients ◽  
Enhanced Absorption ◽  
Model Geometry ◽  
Ball Milling Technique

The purpose of this study was to synthesize high-quality recycled α-Fe2O3 to improve its complex permittivity properties by reducing the particles to nanosize through high energy ball milling. Complex permittivity and permeability characterizations of the particles were performed using open-ended coaxial and rectangular waveguide techniques and a vector network analyzer. The attenuation characteristics of the particles were analyzed with finite element method (FEM) simulations of the transmission coefficients and electric field distributions using microstrip model geometry. All measurements and simulations were conducted in the 8–12 GHz range. The average nanoparticle sizes obtained after 8, 10 and 12 h of milling were 21.5, 18, and 16.2 nm, respectively, from an initial particle size of 1.73 µm. The real and imaginary parts of permittivity increased with reduced particle size and reached maximum values of 12.111 and 0.467 at 8 GHz, from initial values of 7.617 and 0.175, respectively, when the particle sizes were reduced from 1.73 µm to 16.2 nm. Complex permeability increased with reduced particle size while the enhanced absorption properties exhibited by the nanoparticles in the simulations confirmed their ability to attenuate microwaves in the X-band frequency range.

Microwave Permittivity, Permeability, and Absorption of Ni Nanoplatelet Composites

2008 ◽  
Vol 8 (8) ◽  
pp. 3967-3972 ◽  
Author(s):  
Juanjuan Huang ◽  
Yong Qin ◽  
Jiangong Li ◽  
Xingdong Jiang ◽  
Fei Ma
Keyword(s):  
Microwave Absorption ◽  
Complex Permittivity ◽  
High Performance ◽  
Volume Fraction ◽  
Magnetic Loss ◽  
Average Diameter ◽  
Complex Permeability ◽  
Frequency Range ◽  
Dominant Term ◽  
Microwave Permittivity

The Ni nanoplatelets with an average diameter of 75 nm and an average thickness of 10 nm are coated with MnO2 by a simple solution phase chemical method. The MnO2-coated Ni nanoplatelets are dispersed in paraffin wax to form the composite samples of the magnetic filler dispersed in the nonmagnetic insulating matrix. The effect of the Ni nanoplatelet volume fraction on the complex permittivity, complex permeability, and microwave absorption of the composites has been studied in the frequency range of 0.1–10 GHz. The complex permittivity of the composites with different volume fractions of the Ni nanoplatelets is almost constant in the 0.1–10 GHz frequency range. The complex permeability of the composites shows several resonance peaks. Besides the natural resonance peak, the exchange resonance peaks are observed. The composite with 17% volume fraction of Ni nanoplatelets has excellent microwave absorption properties of a minimum reflection loss value −31 dB at 9.1 GHz for a thickness of 2 mm and a broad absorption bandwidth of 2.3–10 GHz (R < −10 dB). The Ni nanoplatelets are a possible candidate as high performance microwave absorption filler. For the Ni nanoplatelet composites, the magnetic loss is the dominant term for microwave absorption.

Preparation of CIP/SiO2/PANI Composites and Design of Electromagnetic Wave Absorption Coating in X-Band

2013 ◽  
Vol 846-847 ◽  
pp. 1905-1910
Author(s):  
Ming Ming Wang ◽  
Wan Jun Hao ◽  
Zhong Lun Zhang ◽  
Guo Yan Hou ◽  
Zhi Jun Xin ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
High Performance ◽  
In Situ Polymerization ◽  
Magnetic Loss ◽  
Complex Permeability ◽  
Frequency Range ◽  
Sem Image ◽  
X Band ◽  
Xrd Patterns

CIP particles first have been coated with SiO2 shell by a Stober process , then grafted the polyaniline by in-situ polymerization to prepare CIP/SiO2/PANI core-shell composites, and the composites are composed the dielectric loss properties with the magnetic loss properties. It is observed that PANI are on the surface of CIP/SiO2 particles from the SEM image, XRD patterns further confirm that the CIP/SiO2/PANI composites are synthesized successfully. In comparison with CIP, the complex permittivity of CIP/SiO2/PANI composites have certain enhancement in 8-12 GHz frequency range, but it has a very small impact on the complex permeability. On the basis of the Electromagnetic Wave Absorbing Theory, the composites could prepare high-performance absorbing coating based on λ/4 type design, and the coating is below-10dB in the whole X-band, which could be used for architectural space electromagnetic radiation protection.

Influence of Milling Time on the Crystallization, Morphology and Magnetic Properties of Polycrystalline Yttrium Iron Garnet

2012 ◽  
Vol 501 ◽  
pp. 324-328 ◽  
Author(s):  
Rodziah Nazlan ◽  
Mansor Hashim ◽  
Nor Hapishah Abdullah ◽  
Idza Riati Ibrahim ◽  
Ismayadi Ismail
Keyword(s):  
Yttrium Iron Garnet ◽  
Annealing Temperature ◽  
Milling Time ◽  
Magnetic Loss ◽  
Milled Powder ◽  
High Energy ◽  
Initial Permeability ◽  
Complex Permeability ◽  
Yttrium Iron ◽  
Iron Garnet

The polycrystalline Yttrium Iron Garnet (YIG) powder with the chemical formula Y3Fe5O12 has been synthesized by using High Energy Ball Milling technique. The effect of various preparation parameters on the crystallinity, morphology and complex permeability of YIG, which includes milling time and annealing temperature were studied respectively by using XRD, SEM and Impedance Material Analyzer. The frequency dependence of complex permeability namely real permeability, µ’ and magnetic loss, µ’’ were measured at room temperature for samples sintered from 600°C to 1400°C, in the frequency range 10 MHz to 1 GHz. The results showed that milling time plays a role in determining the crystallinity of the milled powder where higher milling time results in better crystallinity due to high reactivity of the particles. From complex permeability measurement, it was observed that the initial permeability and magnetic loss increased with increasing grain size. The permeability values increased with annealing temperature and the absolute values of permeability decreased after attaining the natural resonance frequency of the material.

scholarly journals Effects of Recycled Fe2O3 Nanofiller on the Structural, Thermal, Mechanical, Dielectric, and Magnetic Properties of PTFE Matrix

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2332
Author(s):  
Ahmad Mamoun Khamis ◽  
Zulkifly Abbas ◽  
Raba’ah Syahidah Azis ◽  
Ebenezer Ekow Mensah ◽  
Ibrahim Abubakar Alhaji
Keyword(s):  
Electron Microscopy ◽  
High Energy ◽  
Filler Loading ◽  
Complex Permeability ◽  
X Ray Diffraction ◽  
Thermal Expansion Coefficients ◽  
Transmission Electron ◽  
Energy Ball ◽  
Hematite Fe2o3 ◽  
Ptfe Composites

The purpose of this study was to improve the dielectric, magnetic, and thermal properties of polytetrafluoroethylene (PTFE) composites using recycled Fe2O3 (rFe2O3) nanofiller. Hematite (Fe2O3) was recycled from mill scale waste and the particle size was reduced to 11.3 nm after 6 h of high-energy ball milling. Different compositions (5–25 wt %) of rFe2O3 nanoparticles were incorporated as a filler in the PTFE matrix through a hydraulic pressing and sintering method in order to fabricate rFe2O3–PTFE nanocomposites. The microstructure properties of rFe2O3 nanoparticles and the nanocomposites were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). The thermal expansion coefficients (CTEs) of the PTFE matrix and nanocomposites were determined using a dilatometer apparatus. The complex permittivity and permeability were measured using rectangular waveguide connected to vector network analyzer (VNA) in the frequency range 8.2–12.4 GHz. The CTE of PTFE matrix decreased from 65.28×10−6/°C to 39.84×10−6/°C when the filler loading increased to 25 wt %. The real (ε′) and imaginary (ε″) parts of permittivity increased with the rFe2O3 loading and reached maximum values of 3.1 and 0.23 at 8 GHz when the filler loading was increased from 5 to 25 wt %. A maximum complex permeability of 1.1−j0.07 was also achieved by 25 wt % nanocomposite at 10 GHz.

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