Browsing by Author "Abokhadra, A"

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    Characterization of borate glasses doped with copper oxide for optical application
    (SPRINGER, 2019-04) Samir, A; Hassan, Moukhtar A; Abokhadra, A; Soliman, L. I; Elokr, M
    Borate glasses having the formula x CuO-(50-x)B2O3-30Na(2)O-20ZnO where x=0, 0.2, 0.5, 1, 4 and 7mol% were investigated. The samples were prepared using the conventional melt-quenching technique. Physical properties were studied such as; X-ray diffraction, FTIR spectra, and UV-visible transmission. The optical basicity, average electro negativity have been estimated. The estimated optical basicity, unlike electron negativity, exhibits an increase with increasing the CuO content. FTIR spectra show that BO4 ratio decreases with increasing CuO content leading to the formation of non-bridging oxygen's. Some optical parameters such as the optical band gap, band tail width, crystal field strength and the UV and NIR cut off were determined. The transmission spectrum revealed that the glassy samples containing high content of copper oxide behave as bandpass filters at higher content. The characterized parameters of these filters were found to be highly affected by the addition of CuO. In these glasses the broad absorption band observed at the wavelength 550nm is characterized by the existence of Cu2+ ions. The optical absorption and ESR studies suggest that, the Cu-ions exist in the Cu2+ state and act as modifiers by increasing the degree of disorder in the glass network. Hence, the present system behaves as a bandpass filter in the ultraviolet-visible region.
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    Influence of Mg2+ substitution on structural, optical, magnetic, and antimicrobial properties of Mn-Zn ferrite nanoparticles
    (Springer, 2020-02) Ashour, AH; El-Bahnasawy, HH; Soliman, LI; Abokhadra, A; El-Sayyad, GS; Maksoud, MIAA
    Superparamagnetic nanoparticles (NPs) have a prominent interest from researchers in the field of industrial and biomedical applications. Herein, Mg2+-substituted Mn-Zn ferrites with nominal composition Mn0.5Zn0.5-xMgxFe2O4 NPs (x = 0, 0.125, 0.25, 0.375, and 0.5) are synthesized via a facile sol-gel method. The samples after sintered at 1173 K are characterized via the X-ray diffraction technique (XRD), Fourier transform infrared (FTIR) spectroscopy, the energy-dispersive X-ray spectra (EDX), high-resolution scanning electron microscopy (SEM), ultraviolet-diffuse reflectance spectroscopy (UV-DRS), and vibrating sample magnetometer (VSM) technique. The XRD and FTIR patterns reveal that the formation of the cubic phase of Mn0.5Zn0.5-xMgxFe2O4 NPs. Also, small peaks associated with the phase of hematite (alpha-Fe2O3) are observed due to the heating of spinel ferrites. The optical band gap for Mg2+-substituted Mn-Zn ferrites ranges between 1.36 and 1.78 eV. The saturation magnetization is enhanced with increasing Mg2+ concentration. Furthermore, the M-H curves show a typical S-shaped exhibiting superparamagnetic nature for the studied samples. Also, the anisotropy constant enhances as Mg2+ content increases in Mn-Zn NPs. Overall, the results revealed that the Mn0.5Zn0.5-xMgxFe2O4 NPs presented a unique properties, and consequently, they can be candidate materials for transformer's cores, antenna, and switching applications. On other hands, antimicrobial potential of the produced ferrite NPs was estimated towards multidrug-resistant (MDR) yeast and bacteria creating urinary tract infection (UTI). All the prepared ferrite NPs showed a hopeful antimicrobial potential upon all UTI-causing pathogens. Between them, Mn0.5Mg0.5 Fe2O4 NPs at 20 mu g/ml was the most promising ferrite NPs produced superior antimicrobial activity due to the narrow band gap.