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    Crystal structure and peculiarities of microwave parameters of Co1-xNixFe2O4 nano spinel ferrites
    (Royal Soc Chemistry, 2023) Hussein, Marwa M.; Saafan, Samia A.; Abosheiasha, H. F.; Zhou, Di; Klygach, D. S.; Vakhitov, M. G.; Trukhanov, S. V.
    Nanosized spinel ferrites Co1-xNixFe2O4 (where x = 0.0-1.0) or CNFO have been produced using a chemical method. The crystal structure's characteristics have been determined through the utilization of X-ray diffraction (XRD). It has been demonstrated that all samples have a single phase with cubic syngony (space group Fd3m). The lattice parameter and unit cell volume behavior correlate well with the average ionic radii of Co2+ and Ni2+ ions and their coordination numbers. Thus, an increase in the Ni2+ content from x = 0.0 to x = 1.0 leads to a decrease in the lattice parameter (from 8.3805 to 8.3316 angstrom) and unit cell volume (from 58.86 to 57.83 angstrom(3)). Elastic properties have been investigated using Fourier transform infrared (FTIR) analysis. The peculiarities of the microwave properties have been analyzed by the measured S-parameters in the range of 8-18 GHz. It was assumed that the energy losses due to reflection are a combination of electrical and magnetic losses due to polarization processes (dipole polarization) and magnetization reversal processes in the region of inter-resonant processes. A significant attenuation of the reflected wave energy (-10 ... -21.8 dB) opens broad prospects for practical applications.
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    Electrospun PVDF/Barium hexaferrite fiber composites for enhanced electromagnetic shielding in the X-band range
    (Elsevier, 2023) Salem, M. M.; Kenawy, El-Refaie; Zakaly, Hesham M. H.; Ene, Antoaneta; Azaam, Mohamed M.; Edries, Tarek B.; Zhou, Di
    In the contemporary, digitally-driven era, the prevalence of electronic devices has drastically escalated electromagnetic (EM) pollution levels, marking a significant environmental challenge. Electrospun fiber composites of polyvinylidene fluoride (PVDF) and Barium hexaferrite (BHF) were analyzed for their potential usage in X -band electromagnetic shielding applications (EMSAs). Pure PVDF and BHF-PVDF fiber composite were manufactured by needleless electrospinning. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and EM measurements utilizing a vector network analyzer (VNA) are all used to describe the prepared samples. The XRD and FTIR analyses confirmed the successful incorporation of BHF into the PVDF matrix. The results show that adding PVDF to BHF in fiber form enhances the reflection loss (RL), indicating improved electro-magnetic shielding effectiveness (EMSE). The SEM analysis revealed that the fiber composite had a uniform fiber diameter distribution. In contrast, the TGA analysis demonstrated good thermal stability of the fiber composite. Polymer samples were evaluated to enhance gamma radiation and neutron particle attenuation. MCNP5 and Phy-X/PSD software were used to study semi-crystalline fluorocarbon polymer (PVDF) and barium hex ferrite BaFe12O19 (30 wt%) with PVDF (70 wt%). The MCNP5 programme simulated 0.015-15 MeV radiation atten-uation. Additionally, the Phy-X/PSD programme verified the simulated mu values for the chosen Mxenes materials. The MCNP-5 code and Phy-X/PSD results were agreed. The linear attenuation coefficients for the polymer samples ranged from 3.166 to 0.032 cm2.g ? 1 for PVDF and from 73.960 to 0.113 cm2.g ? 1 for PVDF and BHF-PVDF Fiber at photon energies from 0.015 to 15 MeV. Overall, the electrospun fiber composite of PVDF and BHF particles shows promise for EMSAs in the X-band range. The enhanced RL observed in our study suggests that these fiber composites could be used to protect against electromagnetic radiation (EMR) from electronic devices, which is increasingly concerning in today's modern society.
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    Impact of the Ni/Co ratio on structural and magnetic properties in A-site stoichiometric nanosized spinel ferrites
    (Elsevier Sci Ltd, 2023) Hussein, Marwa M.; Saafan, Samia A.; Abosheiasha, H. F.; Zhou, Di; Silibin, M. V.; Trukhanov, S. V.; Trukhanov, A. V.
    We present a meticulous synthesis of Co1-xNixFe2O4 nanoparticles (0.0 <= x <= 1.0) via the chemical citrate precursor technique. Comprehensive X-ray diffraction (XRD) analyses showcased prominent diffraction peaks, especially for the x = 0.0 sample, corroborating the impeccable cubic spinel ferrite structure devoid of extraneous phases. This structural integrity is further evidenced by a linear attenuation in unit cell parameters with heightened Ni2+ ion concentration, a phenomenon seamlessly aligning with Vegard's law and the nuances of the A-site ionic radii. Magnetic characterizations derived from Vibrating Sample Magnetometer (VSM) evaluations reveal a pronounced modulation in primary magnetic parameters with increasing Ni content. This modulation not only resonates with the charge and spin dynamics of the A-site ions but also accentuates the cardinal role of cation distribution between A- and B-sites in magnetic property determination.