Microwave absorbent properties of nanosized cobalt ferrite powders prepared by coprecipitation and subjected to different thermal treatments

Fannin, P.C.; Marin, C.N.; Mălăescu, I.; Stefu, Nicoleta; Vlăzan, Paulina; Novaconi, S.; Sfîrloagă, Paula; Popescu, Simona; Couper, C.

doi:10.1016/j.matdes.2010.08.053

Cited by 43 publications

(37 citation statements)

References 20 publications

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“…Attention has focused on the preparation and characterization of superparamagnetic nanoparticles of metal oxides and spinel ferrites (MFe 2 O 4 ) (M=Co, Mg, Mn, Ni, etc.) [1][2][3][4] . To minimize the difficulties posed by the mixed oxide method, various methods of chemical synthesis have been used in the laboratory to obtain ferrites, mainly in order to control their microstructure and magnetic properties by controlling characteristics such as purity, chemical homogeneity, shape and mean particle size of powders [3][4][5][6] .…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4] . To minimize the difficulties posed by the mixed oxide method, various methods of chemical synthesis have been used in the laboratory to obtain ferrites, mainly in order to control their microstructure and magnetic properties by controlling characteristics such as purity, chemical homogeneity, shape and mean particle size of powders [3][4][5][6] . In the past decade, the solution combustion method was widely used to synthesize single or mixed metal oxides [7][8][9][10][11][12] .…”

Section: Introductionmentioning

confidence: 99%

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Microwave Assisted Combustion Synthesis and Characterization of Nanocrystalline Nickel-doped Cobalt Ferrites

et al. 2016

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)] were prepared by the microwave combustion synthesis, using a stoichiometric mixture of metal nitrates and urea as the oxidizer and fuel to drive the reaction. The effect of microwave irradiation on the phase composition was favorable to promote the formation of fluffy foams and nanoparticles sizes. The fast internal heating with microwaves leads to a reduction in synthesis time, to only 2 min. The structural, chemical and magnetic properties of the nickel-doped cobalt ferrites were analyzed by XRD, TEM, SEM and BET. The XRD results confirmed the formation of pure and single-phase spinel structure. The crystallite size of the nanoparticles was in the range of 38 -50 nm. SEM images show nanoparticles with spherical shape and homogenous morphology. The TEM analysis shows necked near-spherical particles with an average size of ~30 -50 nm, reflecting the highly crystalline nature of these nanoparticles. The magnetic measurements of all the samples were recorded using vibrating sample magnetometer (VSM) at room temperature in 10 kOe. Increasing the nickel content directly affects the structural characteristics of the particles, causing a reduction in the coercive field.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microwave Assisted Combustion Synthesis and Characterization of Nanocrystalline Nickel-doped Cobalt Ferrites

et al. 2016

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“…There are experimental techniques in which the dielectric permittivity and magnetic permeability are firstly measured to determine the reflection coefficient R and the transmission coefficient T [9][10][11]. The common definitions of the electric SE e and magnetic SE m shielding effectiveness at an arbitrary point P within the shielded domain are given by…”

Section: Theoretical Backgroundmentioning

confidence: 99%

The Response of a Magnetic Fluid to Radio Frequency Electromagnetic Field

et al. 2017

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Electromagnetic pollution generated by the electrical devices has been regarded as a new form of pollution, harmful to the society as air and water pollution. The operation of electronic devices in a polluted electromagnetic environment has caused electromagnetic interference to become important concerns. Devices that are vulnerable to interference must often be shielded to protect them from the effects of electromagnetic interference. In this work we describe an interaction of a magnetic fluid based on transformer oil with alternating magnetic field. The magnetic fluid was composed of a transformer oil and dispersed magnetite nanoparticles coated with oleic acid. Among the wide range of topics covered, we pay attention to an important field related to the absorption of electromagnetic field by magnetic fluid as a suitable candidate for applications where it is necessary to electrically isolate, remove excess of heat, and to shield electromagnetic fields. We present a method for the determination of shielding effectiveness of the magnetic fluid under high-frequency excitation conditions from 750 MHz to 3 GHz by means of magnetic near field measurements and analysis. Herein, we report the effect of magnetic volume fraction in the magnetic fluid and the effect of the sample thickness on the shielding effectiveness. We have found that the magnetic fluid has a frequency dependent "windows", characterized that either absorb the magnetic field, or facilitate penetration of the magnetic field through the barrier.

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“…According to the transmission of electromagnetic wave theory [10][11][12][13], when the uniform plane electromagnetic wave injects the bottom layer of the single metal plate absorbing coating vertically, the frequency of which is f, the reflectivity power of electromagnetic wave R for the coating is:…”

Section: Microwave Characteristicsmentioning

confidence: 99%

Microwave Electromagnetic and Absorption Properties of AFe2O4(A=Ni,Mn,Zn) Ferrites

Huang¹,

Yuan²,

Liu³

et al. 2017

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The spinel ferrite (AFe 2 O 4 , A=Ni, Zn, Mn) were prepared under the same condition via sol-gel method. The structure and electromagnetic properties of the powders were characterized by X-ray diffractometer, scanning electron microscope, and vector network analyzer, respectively. These materials were found to be very good catalysts for the oxidation of styrene to benzaldehyde in the presence of hydrogen peroxide. Because of the difference in radius and electrical of these ions (Ni

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Microwave absorbent properties of nanosized cobalt ferrite powders prepared by coprecipitation and subjected to different thermal treatments

Cited by 43 publications

References 20 publications

Microwave Assisted Combustion Synthesis and Characterization of Nanocrystalline Nickel-doped Cobalt Ferrites

Microwave Assisted Combustion Synthesis and Characterization of Nanocrystalline Nickel-doped Cobalt Ferrites

The Response of a Magnetic Fluid to Radio Frequency Electromagnetic Field

Microwave Electromagnetic and Absorption Properties of AFe2O4(A=Ni,Mn,Zn) Ferrites

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