Magnetic,dielectric and electrical modulus of Ce^(3+) doped cobalt-magnesium ferrite nanoparticles

In this work,the magnetic,dielectric properties and electric modulus of Ce^(3+) substituted cobaltmagnesium(Co_(0.7)Mg_(0.3)Ce_(x)Fe_(2-x)O_4)(labeled as CMCF) ferrite nanoparticles were investigated in detail.Saturation magnetization decreases from 50.05 to 34.87 emu/g for further substituting Ce^(3+) ions.Meanwhile,coercivity increases from 738.22 Gs for the CMCFO sample to 912.10 Gs for the CMCF2 sample,then decreases monotonically to 762.1 Gs for the CMCF5 sample.The cerium content and particle size play important roles in controlling the magnetization and coercivity of the CMCF nanoparticles.All CMCF nanoferrites are suitable for microwave applications since their high-frequency response ranges from 7.72 to 11.07 GHz.The CMCF nanoferrites' dielectric parameter dispersion exhibits normal behavior.The pristine Co-Mg nanoferrite only has ε' value of 28.25,but the nanoferrite MCMF2 has ε' value of365.03,with an enhancing ratio of 1192%.The conduction mechanism of the MCMF nanoferrites was determined by fitting the σ_(ac) results via the Jonscher power law.At 653 K,large polaron tunnelling is thought to be responsible for this conduction process,which is followed by electron barrier hopping at higher temperatures.Cole-Cole diagrams at different temperatures,assuring the contributions of the grains and their boundaries at lower temperatures(653 K) and only the grains at higher temperatures.Based on our results,the CMCF nanoferrites hold magnetic and semiconducting nature,which can be used in magnetic devices and dielectrics in lower-frequencies or conductors in higher-frequencies.

Y^(3+) substituting-adjusted mechanical,dielectric,and impedance properties of cobalt copper zinc nanoferrites for high frequency applications

Upgrading mechanical-dielectric features of ferrites through rare-earth yttrium(Y^(3+))doping provides feasibility to evolving high-frequency electronic devices.This paper reports the mechanical and dielectric properties of Co_(0.5)Cu_(0.25)Zn_(0.25)Y_(x)Fe_(2-x)O_(4)ferrite nanoparticles labeled as CCZYF#0,CCZYF#1,CCZYF#2,CCZYF#3,CCZYF#4 and CCZYF#5 for x=0.0.0.02,0.04,0.06,0.08,and 0.1,respectively.The frequency and temperature dependence of dielectric parameters and co nductivity of all CCZYF nanoferrites are well discussed.The nanoferrite CCZYF#5 has the highest dielectric constant(enhancing ratio 170%)and the highest conductivity(enhancing ratio 7125.81%)compared with the undoped sample.Nyquist plots of all CCZYF nano ferrites manifest two arcs;the main reasons for the dielectric process are the grain boundaries and bulk grains.All impedance parameters were determined,which showed the effective role of Y^(3+)ions on their values.The nanoferrite CCZYF#5 has the highest grain boundaries capacitance(with enhancing ratio of 59.40%)and the highest grains capacitance(with enhancing ratio of 22.53%)with a relaxation time decrement efficiency of 62.51%.An ultrasonic flaw detector was utilized to determine the elastic moduli of all CCZYF nanoferrites.The nanoferrite CCZYF#5 has the highest longitudinal modulus(with enhancing ratio of 20.95%),the highest shear modulus(with enhancing ratio of48.72%),highest Young's modulus(with enhancing ratio of 88.47%),the highest bulk modulus(with enhancing ratio 13.27%)and the highest micro hardness(with enhancing ratio 77.77%).Hence,Y3+tuned Co-Cu-Zn nanoferrites possess new opportunities for high-frequency and storage applications.

Intrinsic mechanism and multiphysics analysis of electromagnetic wave absorbing materials: New horizons and breakthrough

Electromagnetic absorbers(EMA) have driven the development of Electromagnetic(EM) technology and advanced EM devices. Utilizing the EM energy conversion of EM absorbers to design various devices is attractive and promising, especially in personal protection and healthcare. In this review article, the simulation and numerical analysis of EM materials are reviewed, from numerical analysis of dielectric parameters, simulation of wave absorbing performance, electromagnetic performance improvement, and structural construction optimization. For the EM response mechanism, radiation-dependent relaxation and charge transport energy transitions are dissected. For the EM calculation section, two leading roles are highlighted, including the purposeful design of EM and the provision of theoretical guidance for optimizing electromagnetic absorption performance. In addition, this work points out the current problems and potential opportunities in the numerical simulation of absorbing materials, points out the new development direction, and proposes prospects.