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 Co2+ substitution on structural, elastic, magnetic, dielectric and optical properties of Mg-Zn ferrite nanoparticles for high frequency devices and photocatalytic application تأثير إحلال أيونات الكوبلت على الخواص التركيبية والمرونة والمغناطيسية والعزلية والضوئية للحبيبات النانومترية لفرايت الخارصين والمغنيسيوم 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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This research was conducted to study the structural, elastic, magnetic, dielectric, and optical properties of cobalt substituted ions in Mg-Zn nanocrystalline ferrite (MZCFO), synthesized using the sol-gel auto-combustion route. The yielded as-prepared powder was characterized by implementing variable characterizing techniques. The XRD patterns assure the formation of the cubic spinel nanocrystalline ferrite for all cobalt concentrations with no trace of any secondary phase. XRD analysis was also applied in determining the experimental average lattice constant (aexp), which estimated to be 0.8389 nm and found in a good agreement with the theoretical lattice constant (ath) that was determined based on the proposed cations distribution. The average crystallite size (D) was found to range between 13nm and 35nm using the Debye-Scherrer method (DDS), and the Williamson– Hall method (DWH). FE-SEM images showed the nanoscale particles of the samples and proved the porous nature, while EDX spectra revealed the entity of all chemical elements (Mg, Zn, Co, Fe, and O). HR-TEM micrographs of the as-prepared MZCFO nanoferrites reveal agglomerated round-shaped nanoferrite particles. Fourier Transform Infrared Spectroscopy (FT-IR) patterns prove the spinel ferrite structure by exhibiting the distinctive vibrational frequencies for the tetrahedral and octahedral sites. Vibrating Sample Magnetometer (VSM) analysis indicates the influence of Co2+ content on the magnetic parameters of the present ferrite. The dielectric constant (ɛ’), dielectric loss (tanδ), and ac conductivity variations with frequency for all samples reveal behavior that can be interpreted based on Maxwell-Wagner interfacial polarization. The variation of the dielectric constant (ɛ’) and dielectric loss (tanδ) as a function of temperature and frequency shows a drastic increase in both (ɛ’) and (tanδ) with increasing the temperature and peaks of various altitudes appear at different frequencies. The ac. electrical conductivity (σ) as a function of temperature at frequencies (50Hz - 5 MHz) was measured for all samples. More than one straight line was obtained, indicating the different conduction mechanisms. One region in the conductivity is due to electron hopping, while the others are due to thermally activated small polaron hopping and magnetic disordering. The real (Z`) and imaginary (Z``) parts of complex impedance were measured as a function of frequency for all samples. Impedance formalism was assessed using Cole-Cole plot, which detects the contribution of grains and grain boundaries in the conduction process. The optical energy gap (Eg) of Mg-Zn ferrite nanoparticles was determined using Tauc's law, which found to tune successfully with the addition of Co2+ ions. The change in (Eg) leads to enhancement in the photocatalytic activity and the degradation efficiency of Methylene Blue (MB) organic dye from 65% to 95%dyes with increasing the addition of MZCFO ferrite under the illumination of visible-light. Based on the discussed findings, this ferrite may consider a potential candidate for multi-functional devices and high-frequency microwave devices, besides the fact that the MB degradation investigation indicates its ability to achieve a peak success in water treatment applications. |
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Supervisor |
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Prof. Salwa Fahiem |
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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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Added Date |
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Sunday, March 14, 2021 |
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Researchers
| نوال سعيد البسامي | Al Bassami, Nawal Saeed | Researcher | Doctorate | |
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