scholarly journals Dielectric and electromagnetic interference shielding properties of high entropy (Zn,Fe,Ni,Mg,Cd)Fe2O4 ferrite

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Adrian Radoń ◽  
Łukasz Hawełek ◽  
Dariusz Łukowiec ◽  
Jerzy Kubacki ◽  
Patryk Włodarczyk
Keyword(s):  
Electrical Conductivity ◽  
Microwave Absorption ◽  
Electromagnetic Interference ◽  
Average Crystallite Size ◽  
Shielding Effectiveness ◽  
Absorption Properties ◽  
Ac Electrical Conductivity ◽  
Microwave Absorption Properties ◽  
High Entropy ◽  
Two Stages

AbstractThe new (Zn,Mg,Ni,Fe,Cd)Fe2O4 high entropy ferrite with average crystallite size 11.8 nm was synthesized in two stages by annealing of co-precipitated amorphous precursor. The dielectric spectroscopy confirms, that the electrical conductivity and polarization processes are associated with the mobility of electrons in the structure of ferrite. It was concluded, that the both, high frequency complex dielectric permittivity as well as complex magnetic permeability are strongly temperature and frequency dependent. The AC electrical conductivity is associated with quantum mechanical tunneling of electrons and related to the transfer of charge carriers between Fe2+ and Fe3+ ions. Moreover, the microwave absorption properties were determined. The best microwave absorption properties have been confirmed in the frequency range 1.9 to 2.1 GHz for a layer which is 0.8–1 cm thick. For this range, reflection loss (RL) is lower than −25 dB and shielding effectiveness (SE) lower than −50 dB.

Magnetic and Microwave Absorption Properties of Magnetite-Durian Shell Nanocomposite Sheet in Gigahertz Range

2018 ◽  
Vol 775 ◽  
pp. 217-223
Author(s):  
Afraha Baiti Arif ◽  
Rose Farahiyan Munawar ◽  
Qumrul Ahsan ◽  
Maisarah Abu
Keyword(s):  
Microwave Absorption ◽  
Electromagnetic Interference ◽  
Filler Content ◽  
Spherical Shape ◽  
Constant Thickness ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Weight Percentage ◽  
Durio Zibethinus

In this paper, a novel microwave absorber of thin, light weight, flexible, green and low cost magnetic nanocomposite sheet that can work in high frequency range is fabricated. The vast and increasing numbers in electronic and telecommunication devices has create electromagnetic interference (EMI) in which may lead to application disturbance. Therefore, electromagnetic (EM) wave absorber with the ability of high absorption rate is strongly demanded. Here, durian shell (Durio zibethinus Murray) embedded magnetite (Fe3O4) nanocomposite sheets were prepared via pulping and lumen loading technique. The nanocomposite sheets were fabricated by varying the weight percentage of the filler content (2-10 wt% of Fe3O4) at constant thickness and varying the thickness of the sheets (0.1-1.0 mm) at constant filler content. FESEM micrograph shows that the Fe3O4 nanoparticles are in cubical and spherical shape with the 20–50 nm of size range. The microwave absorption properties of the sheets were tested by a vector network analyze (VNA) in the frequency range of 4-18 GHz. The samples were also tested using vibrating sample magnetometer (VSM) in order to study the magnetic properties. The absorption or maximum reflection loss (RL) of the samples increases continually and the increase of both filler content and sample thickness has led to the shift of dip to lower frequency region.

EFFECT OF Nd-DOPING ON THE NANOCRYSTALLITE SIZE AND MICROWAVE ABSORPTION PROPERTIES OF Sr-HEXAFERRITE

2011 ◽  
Vol 04 (03) ◽  
pp. 283-287 ◽  
Author(s):  
H. KHANMOHAMMADI ◽  
S. A. SEYYED EBRAHIMI
Keyword(s):  
Crystallite Size ◽  
Microwave Absorption ◽  
Average Crystallite Size ◽  
Strontium Hexaferrite ◽  
Resin Matrix ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Calcination Temperatures ◽  
Nanocrystallite Size ◽  
Scherrer Formula

Nd -doped M -type Strontium hexaferrite powders with composition of Sr 1-x Nd x Fe 12 O 19(x = 0, 0.1, 0.2) were prepared by conventional ceramic method at various calcination temperatures. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for characterization of the obtained powders. The results showed that by increasing Nd doping, the single phase magnetoplumbite structure has been formed at higher temperatures. The average crystallite size of the samples calculated by the Scherrer formula indicates that Nd -doping resulted in a significant decrease in the mean crystallite size. The hexaferrite-polymer bulk composites in epoxy resin matrix, with ferrite ratio of 90 wt.%, were also prepared. The microwave absorption properties of these composites were investigated in 8–12 GHz frequency range by means of a vector network analyzer. Due to the reflection loss measurements, Nd -doped Sr -hexaferrite could be a promising material for microwave absorption applications in X-band.

Enhanced microwave absorption properties of PMMA modified MnFe2O4–polyaniline nanocomposites

2019 ◽  
Vol 21 (9) ◽  
pp. 5068-5077 ◽  
Author(s):  
R. V. Lakshmi ◽  
Parthasarathi Bera ◽  
R. P. S. Chakradhar ◽  
Balamati Choudhury ◽  
Shital Patangrao Pawar ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Microwave Absorption ◽  
Polymethyl Methacrylate ◽  
Electromagnetic Interference ◽  
Solution Combustion Synthesis ◽  
Emi Shielding ◽  
Solution Combustion ◽  
Absorption Properties ◽  
Microwave Absorption Properties

Nanocomposites consisting of polymethyl methacrylate modified MnFe2O4 prepared by solution combustion synthesis and polyaniline exhibit enhanced electromagnetic interference (EMI) shielding property.

Sign in / Sign up

Export Citation Format

Share Document