Magnetization and Microwave Absorption Properties of La0.67 Sr0.33 MnO3 with Different Particle Size

2011 ◽  
Vol 374-377 ◽  
pp. 1541-1544 ◽  
Author(s):  
Yu Lan Cheng ◽  
Ping Xia ◽  
Ke Xiang Wei ◽  
Quan Bai

La 0.67 Sr 0.33 MnO 3 particles with different particle size have been prepared by sol-gel method. The structure, magnetization and microwave absorption properties have been investigated. The results show that the particle size can be controlled by sinter temperature. The peaks of the maximum reflection loss (RL) move to higher frequency regions with increasing particle size. The value of the maximum RL is -32 dB at 10.2GHz with a particle size of 58.5nm. The bandwidth with a RL exceeding -8dB reached 1.6GHz in the whole measured frequency range, suggesting that La 0.67 Sr 0.33 MnO 3 particles are promising for application as a wideband and strong absorption building microwave absorber.

RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86656-86664 ◽  
Author(s):  
Hongyu Wang ◽  
Dongmei Zhu ◽  
Wancheng Zhou ◽  
Fa Luo

The maximum reflection loss value of polyimide/Ti3SiC2 composites is up to −48.6 dB at 8.5 GHz with a thickness of 2.9 mm and the absorption bandwidth below −10 dB is 3.8 GHz.


2017 ◽  
Vol 1142 ◽  
pp. 211-215 ◽  
Author(s):  
Wang Jun Feng ◽  
Xing Zhao ◽  
Wen Qian Zheng ◽  
Jun Tao Gang ◽  
Yue Cao ◽  
...  

The BaFe12O19 nanoparticles was prepared by sol-gel method in different temperature (750°C,850°Cand 950°C), and then BaFe12O19/polyaniline nanocomposites was synthesized by in situ polymerization. The XRD, FTIR spectra, SEM and vector network analyzer were used to analyze the "" chemical component, morphology and microwave absorption property of the nanocomposites. The result show that BaFe12O19 can be generated at 750°C without any impurity ,and its size increased with increase of calcination temperature.BaFe12O19 nanoparticle was coated with polyaniline partially, and we can get it have interaction with polyaniline through FTIR spectra. While the ferrite calcined at 850°C,the thickness of the absorbing material is 4.5mm,the nanocomposites have the largest reflection loss of-17.6 dB at 6 GHz,and its reflection loss values less than−10 dB in the range of 5-7.4GHz.


RSC Advances ◽  
2019 ◽  
Vol 9 (37) ◽  
pp. 21243-21248 ◽  
Author(s):  
Chao-Qin Li ◽  
Xun Shen ◽  
Ruo-Cheng Ding ◽  
Guang-Sheng Wang

A Mo2C@C/PVDF composite with excellent absorption performance has been synthesized. The results indicate that the maximum reflection loss can reach −39.0 dB, and the absorbing bandwidth is up to 3.1 GHz at a thickness of 2.0 mm.


2010 ◽  
Vol 148-149 ◽  
pp. 893-896 ◽  
Author(s):  
Ze Yang Zhang ◽  
Xiang Xuan Liu ◽  
You Peng Wu

M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were successfully prepared by the sol-gel method and solution phase reduction method, respectively. The crystalline and morphology of particles were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The composite coatings with SrFe12O19 ferrites and FeNi3 nanoplatelets in polyvinylchloride matrix were prepared. The microwave absorption properties of these coatings were investigated in 2-18GHz frequency range. The results showed that the M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were obtained and they presented irregular sheet shapes. With the increase of the coating thickness, the absorbing peak value moves to the lower frequency. The absorbing peak values of the wave increase along with the increasing of the content of FeNi3 nanoplatelets filling fraction. When 40% SrFe12O19 ferrites is doped with 20% mass fraction FeNi3 nanoplatelets to prepare composite with 1.5mm thickness, the maximum reflection loss is -24.8 dB at 7.9GHz and the -10 dB bandwidth reaches 3.2GHz.


2020 ◽  
Vol 46 (4) ◽  
pp. 4329-4334 ◽  
Author(s):  
Liang Zhou ◽  
Jiaojiao Yu ◽  
Zhenjun Wang ◽  
Hongbo Wang ◽  
Julong Huang ◽  
...  

2015 ◽  
Vol 645-646 ◽  
pp. 126-131
Author(s):  
Qing Guo Ren ◽  
Xiao Jing Qiao ◽  
Yan Li ◽  
Zhi Gang Sun ◽  
Xiao Dang Guo ◽  
...  

Monodisperse CoFe2O4and Co0.4Zn0.6Fe2O4hollow nanospheres were synthesized in large scale by solvothermal method in ethylene glycol solution. The structure, shape and size of the samples were investigated by Fourier Transform infrared, X-ray powder diffraction and scanning electron microscopy. The results indicate that the products are spherical with an average diameter less than 200 nm. Magnetic studies revealed that the saturation magnetization of Co0.4Zn0.6Fe2O4is 78.6 emu/g, higher than the CoFe2O4, which is 69 emu/g, while the coercivity of the Co0.4Zn0.6Fe2O4is 184 Oe , obviously lower than that of CoFe2O4which is 832 Oe. The electromagnetic parameters were measured at 2-18 GHz using HP8722ES vector network analyzer and then the microwave absorption properties were calculated through the transmission line theory. As to the Co0.4Zn0.6Fe2O4, the absorption bandwidth with reflection loss below-10 dB is up to 3GHz, from 10GHz to 13GHz with a thickness of 2 mm. A maximum reflection loss-45.6 dB was found at 12.9 GHz for the CoFe2O4with a thickness of 1.8 mm. As a result, the as-prepared hollow nanospheres show good prospects of being applied in EM wave absorption materials.


2018 ◽  
Vol 775 ◽  
pp. 217-223
Author(s):  
Afraha Baiti Arif ◽  
Rose Farahiyan Munawar ◽  
Qumrul Ahsan ◽  
Maisarah Abu

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.


2013 ◽  
Vol 631-632 ◽  
pp. 429-433 ◽  
Author(s):  
Yan Qiu Chu ◽  
Bin Zhang ◽  
Jun Xiang

Ni0.5Zn0.5Fe2O4, Ni0.3Cu0.2Zn0.5Fe2O4 and Ni0.4Co0.2Zn0.4Fe2O4 spinel ferrite nanofibers with 60–100 nm in diameter were fabricated through the sol-gel assisted electrospinning method, followed by calcination at 600°C for 2h in air. The phase structure morphology and element composition of these nanofibers were determined by XRD, FE-SEM and EDS. Magnetic measurements were used to justify the ferromagnetic properties of these nanofibers. Microwave absorption, which was in the range of 2-18 GHz, was studied by a vector network analyzer. The adoption of Cu2+ and Co2+ substitution was found to improve the microwave absorption in relation to non-substituted NiZn ferrite nanofibers. Reflection loss exceeding –5 dB is obtained between 11 and 18 GHz for silicon rubber composites containing 15 vol% nickel-based ferrite nanofibers with coating thicknesses of 3 mm. The results indicate that the prepared nickel-based ferrite nanofibers possess good electromagnetic wave absorption performance in the Ku band and have great potential as microwave absorber for practical applications.


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