Document Details
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Document Type |
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Thesis |
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Document Title |
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Effect of Cu2+ substitution on structural, elastic, magnetic, dielectric and optical properties of magnesium zinc ferrite nanoparticles for high frequency devices and photocatalytic applications تأثير إحلال ايونات النحاس على الخواص التركيبية والمرونة والمغناطيسية والعزلية والضوئية للحبيبات النانومترية لفرايت الخارصين والماغنسيوم ومجالات تطبيقاتها في أجهزة الترددات العالية وكمحفزات ضوئية |
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Subject |
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Faculty of Science |
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Document Language |
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Arabic |
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Abstract |
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The ferrite nanoparticles Mg0.8Zn0.2-xCuxFe2O4; (0≤x≤0.2; step 0.04) (MZC) were prepared by the citrate combustion using citric acid as fuel. The final products of MZC NPs were characterized by XRD, FTIR, FE-SEM, HR-TEM, VSM analysis besides their elastic, dielectric and optical properties. X-ray diffraction analysis indicates that all the samples were formed in a single phase spinel structure. The broad XRD peaks expose the nano-crystalline nature of the investigated MZC samples. From Williamson-Hall plots, the crystallite size spans between 37-47 nm with positive lattice strain. The experimental lattice parameters (aexp) of all MZC nanoferrites were calculated from the XRD data. The lattice parameter doesn't introduce a decrement behavior. Fourier-transform infrared (FTIR) spectra realize the two finger print characteristic infrared absorption bands of ferrites and the values of the bands are changed with Cu2+ substitution, due to cations distribution. FESEM depicts nano-sized spongy shapes with entity of porous. EDAX spectra divulge the entity of all chemical elements. HRTEM and SAED micrographs confirmed the polycrystalline nanosized essence of samples. Elastic properties of MZC nanoferrites can be securitized either theoretically, basing on FTIR analysis, or experimentally by ultrasonic technique. Crystallite size was the main reason for nanoferrite Mg0.8Zn0.04Cu0.16Fe2O4 (x=0.16) to have the highest elastic moduli comparing with the virgin nanoferrite; where Young's modulus is doubled. The magnetic hysteresis loops for all prepared samples were carried out at room temperature. From these loops we determined the saturation magnetization (Ms), remnant magnetization (Mr) and the coercive field (Hc).Cations distribution and crystallite size claimed responsibility for the nanoferrite Mg0.8Zn0.12Cu0.08Fe2O4 (x=0.08) to have the highest saturation magnetization (43.39 emu/g) with the lowest coercive field (72.79G). The frequency and temperature dependence of dielectric constant (έ) and dielectric loss tangent (tanδ) and conductivity (σ) at room temperature at frequencies (100Hz - 5MHz) and (303-845K) were studied. The ac. electrical conductivity curves have more than one straight line was obtained, indicating the different conduction mechanism. One region in the conductivity is due to electron hopping which the others are due to thermally activated small polaron hopping and magnetic disordering. The real part (Z′) and imaginary part (Z′′) of the complex impedance Z* of MZC nanoferrites are calculated. The frequency dispersion of Z′ for MZC nanoferrites at 303 K; introduces high values at lower frequency and decay at higher one. These curves exhibit peaks at definite frequency which denotes relaxation phenomenon for each MZC nanoferrite. The Nyquist plot of the MZC nanoferrites, at 303 K, over a frequency range of (50 Hz to 5 MHz), introduces one semicircle at lower frequency is owing to grain boundary. The optical properties of MZC nanoferrites have been estimated using the UV–Vis spectroscopy and their optical band gaps (Eg) were calculated using Tauc’s Eq. The decrement behavior in Eg values can be understood based on the increase of conductivity in MZC samples. The degradation efficiency of RhB over MZC photocatalyst is enhanced comparing with that of pristine RhB. The nanoferrite Mg0.8Cu0.2Fe2O4 (x=0.2) has the optimal merits; highest dielectric constant, conductivity, photodegradation percentage, besides lowest energy gap. All these advantages make it an auspicious candidate for electronic application (especially for high-frequency applications and transformers cores) and wastewater treatment process. |
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Supervisor |
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Prof. Salwa Mansour |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1442 AH
2020 AD |
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Co-Supervisor |
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Prof. Faten Al-hazmi |
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Added Date |
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Saturday, March 6, 2021 |
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Researchers
| نور محمود بصفر | Basfar, Noor Mahmoud | Researcher | Doctorate | |
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